opensource ip pbx

http://chayden.net/Asterisk/SeUpAsteriskAtHome.htm

http://www.gnu.org/software/bayonne/

http://www.openh323.org/

http://www.gnugk.org/

http://toncar.cz/openh323/tut/

http://www.gnugk.org/h323manual-zh.html :這個很仔細，step by step, 中文

http://sourceforge.net/projects/openippbx

這個網站將asterisk裝在CF中(含有cf image 可以download): http://www.automated.it/asterisk/asterisk-cf.htm