A recent thread on the Ham Radio Help Group is discussing where to find homebrew information. Here are some mailing lists that were mentioned:
http://groups.yahoo.com/group/HamBrewers/
http://groups.yahoo.com/group/radioexperimenter/
http://groups.yahoo.com/group/VHF_UHF_homebrew/
http://groups.yahoo.com/group/radiokits/
The radioexperimenters group is currently converting cheap FRS radios into 70 cm amateur band radios using a PIC microcontroller. Later, they plan to use it for data transmission of GPS and packet data.
Anyone know of any others?
http://groups.yahoo.com/group/emrfd
From their banner:
Gathering place to discuss experiments, projects, improvements, etc., and technology in the same vein as that found in the ARRL publication “Experimental Methods in Radio Frequency Design.”
73 Kent VE4KEH