If you know what PBX means or know what it implies, then you will definitely want to check this out. www.trixbox.org
Previously called Asterisk @ home, TrixBox is a complete OpenSource PBX solution. Asterisk @ home gave even me the impression it was not intended for other use except a single phone line. Well I was wrong to assume this, as many of you may have assumed this too.
I just downloaded the iso and started the install. I’ll keep you posted how it goes.