I’ve installed Asterisk on two machines now, an old PowerMac G3 and a Linux box running Fedora. It all went pretty smooth. Configuration is another issue.
While I’m not a huge phone-dork like some people, Asterisk is cool to hack at. I managed to get Xten’s X-Lite SIPphone working with it, though I’m getting a bunch of crashes on one machine that I’m not sure if they are due to my Mac, or the Linux box. I’ll keep hacking at it.
My ultimate goal is to be able to use my Asterisk box which sits at home, behind the firewall as an answering machine for SIP calls from the internet. Not sure if that’s (easily) doable, but it’s worth a try. The Asterisk section of the VOIP-info wiki should come in handy.