Single board computers

RouterBoard

I currently am experimenting with a RouterBoard 532A (about $200 including a case and power supply).

Support for it in OpenWrt seems to be pretty good, they have the latest releases prebuilt for it. I used instructions in this page to get it loaded. It took 10 minutes. http://wiki.openwrt.org/OpenWrtDocs/Hardware/Mikrotik/RB532?highlight=%28OpenWrtDocs/Hardware%29

Support in dd-wrt is not good. There is an old beta.

Manufacturers

PC Engines makes WRAP boards, $129

Soekris boards are also popular for WiFi projects.

RouterBoard 133 model is just $59

PepLink makes load balancers, WAPS, and a general purposes gateway router/switch box calld the Manga. See also "Debian in 3 watts". This shows how to set up a Manga to run Debian from a USB storage device.

Metrix Wireless development kits