For the Linux people out there, Linux Journal (http://www.linuxjournal.com) has an article by Patrick Deegan in the February 2005 issue titled Developing for the Atmel AVR Microcontroller on Linux.
Looks to be the complete how-to on setting up to develop code under Linux for the AVR platform.
Here's how Freaks is listed in the online resources section: "AVR Freaks, freakishly into AVRs. Check out their device comparator and AVR academy: www.avrfreaks.com."
Here is the link to the online resources for AVR page: http://interactive.linuxjournal.com/article/7920