An Intro to OpenSim: The Apache of Virtual Worlds

ajohnj1 writes: "You've probably read a bit about OpenSim, the BSD-licensed virtual world server, and recent news that IBM and Linden Lab are working to make Second Life and Open Sim interoperable. Besides that project, what's Open Sim about, who's working on it, what are they doing with it, and how do you get involved as a developer and participant? Here's a starter's guide."