Here are some links to some really cool stuff relating to Rubik's cubes:

This web site has the best virtual rubik's cube program I could find: The Magic Cube
This web site will show you a step by step solution to the puzzle from any position you enter in: CUBE-The Rubik's Cube Solver
If you ask me, these guys are perhaps a little too obsessive, but here you are: Rubik's Cube Art
These guys have the whole 4D Rubik's HyperCube thing worked out: Magic Cube 4D
For a history of the cube and some other fun games, here's the official site: Rubik's Online