Geek.com have updated their classic tutorial on how to set up your own PBX (Private Branch Exchange) or switchboard phone system.
This article demonstrates how easy it is to roll your own PBX in about an hour or two. Provided that the instructions herein are followed carefully, you too should be able to set up your very own switchboard/PBX system and all for the cost of the target hardware of your choice.
We have just fully virtualized our office using PBX in a Flash . Customers call local numbers and are routed invisibly to wherever our operation is awake at that time. We have every feature one would expect from a top of the range Switchboard system, but it is completely free.
Everything is hosted on a tiny and inexpensive Virtual Grid Server (VGS) , but could as easily be hosted on an ancient and unused old Pentium 2 with a decent internet connection.
[UPDATE: Jarvis Whyte alerted me to a superb looking application called CallButler, open source PBX built on .NET. If you are a windows house, this may well be perferct for you. Thanks Jarvis.]