Hacking in Asterisk and Rails
Joe Heitzeberg is a former coworker of mine from Avogadro and Openwave and a great guy.
He has a new startup called Snapvine and an Oreilly article called Hacking in Asterisk and Rails, which you should definitely read if you’re interested in VOIP and/or Rails. They’ve created the open source framework ragi, which connects Rails and the open source PBX Asterisk.