Worlds Shaper tutorial after I had my go at it.
http://files.worlio.com/users/aujourd/matrixtest.world
I have started adding Kiosks to link to and from each world.
Ground Zero
/x/ - Unsure of the author but I suspect GradualDIME.
MTV's vLES or Virtual Lower East Side. The project was jumpstarted on a Mac platform in a 3D world that resembles Second Life. The world's version is the work of Jimbly and 2 others, I am told.