Testdrive: Digium's Asterisk IP PBX

It's another "open source" Linux package. Definitely an interesting option for the small techno savvy operation. We even tested it with a couple of downloadable open source additions for the main voice routing software -- an Admin GUI and a voicemail client. Certainly not as polished as most mainstream systems, but, again, might be worth a look for those not all that interested in traditional telephony polish; it's certainly a cheap option.