Radio maddness

Digital Radio in the AM bands. FM quality with AM reach, plus digital goodies like song/artist/album info.
http://www.drm.org/whydigital/globwhats.htm
http://drm.sourceforge.net/

Micropower FM broadcasting:
http://www.freeradio.org/index.php?pagename=frb/about.html

An opensource (firmware and schematics too!) Portable music player:
http://www.neurosaudio.com/
http://open.neurosaudio.com/