VOIP (Voice Over Internet Protocol) is hot these days. Every ISP (Internet Service Provider) or cable company is starting some VOIP-business so you can call via the internet.
But you can also do what the big companies do if you have a lot of free time on your hands. Got a spare Pentium III pc somewhere which is good enough to run a Linux distribution? Why not set it up as a PBX? Get the trixbox ISO here.
Asterisk based trixbox enables even the novice user to quickly set up a voice over IP phone system. trixbox can be configured to handle a single phone line for a home user, several lines for a small office, or several T1s for a million minute a month call center.
Unfortunately the support on this free piece of software is quite horrible. The linux distribution seems to have serious bugs and it’s quite a pain to get “weird” hardware like Cisco cards up and running.
You will also need Linux skills if you plan to update the software or get it working via the internet.
Con: serious skills required