http://www.wlug.org.nz/AsteriskSipPhoneSetup
http://www.jeremy-mcnamara.com/2007/02/26/how-to-configure-asterisk-your-first-installation/
http://asteriskathome.sourceforge.net/handbook/
http://www.voip-info.org/wiki-Asterisk+config+sip.conf
http://www.howtoforge.com/asterisk_pbx_linux
http://www.asteriskguru.com/tutorials/asterisk_voip_ipphone.html
http://phplinuxandthelike.wordpress.com/2007/07/30/asterisk-and-fedora-core-7/