FOSS in the Mobile World
Links

OpenBSC
http://openbsc.gnumonks.org/
3GPP / ETSI GSM Specs
http://www.3gpp.org/
Priv-Doz. Dr.-Ing Joachim Goeller
http://www2.informatik.hu-berlin.de/~goeller
THC GSM Wiki 
http://wiki.thc.org/gsm
OpenBTS
http://gnuradio.org/trac/wiki/OpenBTS
Harald's branch of gsm-tvoid, etc
git://git.gnumonks.org/gsm.git