Apple Airport Stuff:
Go here for a good collection of Apple Airport Base Station (ABS) mods and experiences.
Apple was the first company to produce a relatively low-cost 802.11b access point in 1999. It was priced at the then-unheard-of $299, when others such as Lucent and 3Com were doing brisk business with essentially the same hardware at $799 and above! It is usually referred to as Pogo (Apple's internal project name), or Graphite. It had a single Ethernet port.
The next in the series was called "Snow", because its white color was a real contrast to the Graphite's silver-grey look. It is also 802.11b-only. Like the newer Extreme line, it had two Ethernet ports so that wired computers could also share connectivity with the wireless ones.
In January 2003, Apple introduced the Airport Extreme access point, announced at MacWorld. Apple was the first company to ship pre-standardized 802.11g product in quantity. Even though the Extreme products shipped before 802.11g became an official standard, various firmware and software upgrades were offered by Apple so that the product line was compliant when the standard was finalized about 6 months later. There was never a need to update the hardware, which is a typical Apple move that protects its early adopters from premature obsolescence. This base station is most often called the AEBS, for Airport Extreme Base Station.
In June 2004, Apple announced the Airport Express. It is the first Apple base station that is not UFO-shaped. It looks very similar to the white power supplies that Apple has used for its G4-based iBooks and Powerbooks. Like the power supplies, it can be plugged directly into a wall outlet. Because of its small size and ease of use, it is popular as a business traveler's accessory. It can be plugged in to a wall outlet and connected to a hotel's in-room Ethernet connection, giving the convenience of instant wireless portability where none exists. It has a single Ethernet port, a USB printer port, and a combination optical/analog audio output jack. It is an unusual design, functioning as either a normal base station/router/access point, OR as a client that can output high quality music while also hosting a printer. I have one in my home set up in this configuration.
At MacWorld 2007, Apple introduced the latest wireless access point, also called the Airport Extreme, although its features and even physical appearance are substantially different than the 2003-era product. The new Airport Extreme (Extremier?) features draft-802.11n support, including 5 GHz band coverage. So 802.11a/b/g/n are all covered. The new access point also includes additional 10/100 LAN ports for client computers. Previously, an Ethernet hub or switch was required if you wanted to connect more than one wired computer to the access point. The USB port also supports new connectivity, such as hard drives.
By the way, you should know that the printer connected to the USB port becomes instantly Bonjour-enabled. Based on the open-source ZeroConf project, Bonjour allows any computer (Mac, Windows and Linux too!) to very quickly and easily discover various peripherals without knowing their IP addresses. Sort of like Microsoft's proprietary UPnP technology, but it works much more seamlessly and intuitively, and without the security risks that UPnP introduces. Bonjour is open-source, and free for the taking. I use it on my Windows XP machines at home, and they see my HP Photosmart printer connected to my Airport Express without any fuss. You can download the Windows Bonjour client here (look down the page for the Windows link). Why is there no Mac OS client? It's built in, of course! Very much recommended, even if you don't use Apple gear. I'll bet Microsoft wishes they could've acquired it first! For more info, click here to go to the ZeroConf.org web page.
See this page for a good spreadsheet-like comparison of the various features on the Airport base stations.
Linksys and Similar Access Points:
OK, now I'm not a huge fan of Linksys gear, but they are cheap and hackable! Please note that, even though I refer mostly to Linksys access points here, many of the following links have info on modding similarly-designed brands such as Buffalo, Asus and others.
LinksysInfo.org has good info on modifying Linksys 802.11 routers, access points, and other non-wireless gear.
Go to SveaSoft.com for a neat hack for the Linux-based Linksys WRT54G router. This guy's reverse engineered the OS, and done a great job of providing a bunch of new features, including compatibility for WDS (Wireless Distribution System) with other companies' routers and access points (including Apple's Airport Extreme series). The last stable image is usually available for free download.
Seattle Wireless also has a very good page covering mods and info on the WRT54G.
The OpenWRT project has lots of good info on putting Linux on Linksys (especially the WRT series), Netgear and other consumer-grade wireless routers. Not for the faint of heart; requires good working knowledge of Linux. Lists quite a few interesting mods like adding GPS or an LCD display to your router. Also has quite a bit of info on what type of hardware is running on various brands of routers.
The HyperWRT project has a slightly less aggressive philosophy. They attempt to stay closer to the official Linksys released firmware while adding some additional features and functionality. Typical added features are more port-forwarding options, more flexible radio and antenna choices, and added quality-of-service (QOS) abilities.
dd-wrt.com is another WRT54G variant worthy of consideration. It is maintained by a fine German guy with the non-threatening name of BrainSlayer. DD-WRT came to life based somewhat on the unhappiness with Sveasoft charging $20/year for their WRT firmware. Once based on Sveasoft's Alchemy release, it has now passed it up with new enhancements. It, as well as some of the others listed here, also works with some Buffalo, Siemens and Asus access points.
Roll your own/Community Wireless:
There are lots of reasons to make your own wireless LAN system. Maybe it's just to extend your home DSL connection a few doors down to your friend or family (hey, I didn't say it was ok--check your broadband provider terms-of-service agreement. If you have Speakeasy, you're good to go, though.). Maybe it's to provide broadband wireless access to your neighborhood where no wired access exists. Maybe you're wiring up a village in Africa. Anyway, there are a number of good-to-great systems that can be created from scratch. One way to start is to get a good, solid computer platform to start with. I don't recommend a "normal" PC with spinning fans and hard drives--it's guaranteed to die sooner than later. You should avoid as many moving parts as possible. You could also do worse than use a Linksys box with one of the various firmware ports listed above. Many others have gone this route. One guy I know of even sells a complete system with weatherproof box, integrated 14 dBi antenna, power-over-Ethernet, etc., and it's using a Linksys WRT-54G inside (minus the blue/black plastic box, I hope).
Here are a number of links to various wireless-enabled Linux or BSD builds that run on a PC, Linksys, Soekris or Wrap processor:
NYC Wireless Pebble LInux. Look here for a good how-to on installing Pebble on a Soekris 4521 board.
LocustWorld.com, home of the unusual-but-cool MeshAP
Leaf (Linux Embedded Appliance Firewall)
The StompBox Project integrates a Verizon or Sprint EV-DO 3G card with an 802.11 access point
Some folks have outfitted the m0n0wall BSD firewall with wireless capabilities, although it works great as a non-wireless firewall, too.
Soekris Engineering makes some great single-board computers ideal for rolling your own access points, routers, etc. I've had very good experiences with their Net4801. It uses a 266 MHz x86-compatible Geode processor, with 128 MB of RAM, a compact flash socket, has 3 Ethernet ports, 2 serial ports, a USB port, a 3.3v PCI connector, a miniPCI connector, watchdog timer, general-purpose I/O, and other goodies. You can put together a Linux or BSD OS that runs entirely out of less than 32 MB of compact flash, so no disk drives are needed. I've done several of these using various distributions. Without adding any wireless cards, you can also use such a box as a really customizable home router or IP PBX phone system.
Netgate sells wireless cards you can plug in to the Soekris boxes. The also sell antennas, cables, and other needful things. One good reason for not using the ready-to-wear Linksys gear above and instead going with a custom Soekris box with, say, a Netgate dual band 2.4/5 GHz miniPCI card is so that you can provide connectivity to clients via 2.4 GHz 802.11b, while using the 5 GHz 802.11a link as your backhaul. This would provide a totally wireless infrastructure. One of the real problems that the designer/operator of a community wireless network faces is backhaul infrastructure. If you look around on the Netgate site, as well as other similar purveyors of gear to community WLAN operators, you'll see some boxes similar to the Soekris that are already set up, ready to use, with a weatherproof enclosure, and usually running some version of *nix in flash. Very reliable and cheap combination.
Take a look here for Tom's Networking review of the PC Engines' WRAP single-board computer, a competitor to the Soekris 4801. The PC Engines page also has quite a few links to compatible wired and wireless *nix distributions that are compatible with it.
While we're on this subject, Tom's Networking has a good how-to on creating a wireless captive portal system using m0n0wall. This is the type similar to a T-Mobile hotspot, where you open a browser after connecting to the open wireless access point, and get a "log in" or "sign up" page before you can surf freely (well, after paying). Good for security, and easy to maintain, since users don't have to know a WEP key or secret code other than their own login info. This particular how-to covers only a simple setup where users must first read a Terms-of-Service agreement, then click on an "I agree" button to proceed. Does not do hardcore user authentication, which would require a Radius server, but that is doable with this system. Also provides a good intro to m0n0wall.
Future subjects to be covered in more detail:
UltraWideband (UWB): Ultra-Wideband entry in Wikipedia
Family Radio Service, CB, GMRS:
Wikipedia entries for:
Satellites & Space Comms: Artificial Satellites entry in Wikipedia
2-way Radio, Police, Fire, etc:
Wi-Fi Planet.com also has some tutorials and hacking info that are worth looking at
Wi-Fi Net News