How does FreeSWITCH compare to Asterisk? | FreeSWITCH
http://freeswitch.org/node/117 Asterisk vs FreeSWITCH (from lead freeswitch developer’s POV)
Pbx
Skype for Asterisk - Product Overview
http://www.skype.com/intl/en/business/products/pbx-systems/asterisk/ “channel skype” asterisk module, allows you to connect your asterisk box to skype
Response Point Home Page
http://www.microsoft.com/responsepoint/default.mspx Home page for small IP PBX appliance from microsoft – very interesting