Here's my partial disassembly. It'll only help you to the point where you detach the screen from the base. I only wanted to fix the USB port, the screen was fine on my N900, didn't need to take it apart.

http://sites.google.com/site/svcr0c0/n900

Before you start working on the screen itself, make sure whenever you tighten screws that they are going in straight. If you crossthread them or if you overtorque them, they'll snap off. Remember, this is a cellphone not a car drive shaft.

Here's a clip of a complete disassembly:

http://www.youtube.com/watch?v=aVEHm325-z8