at the following page there are schematics for 8-bit and 4-bit mode as well as source code for gcc:
hxxp://jump.to/fleury
at hxxp://www.geocities.com/dinceraydin/djlcdsim/djlcdsim.html there ist a javascript that simulates a LCD. so you can set and clear each control and data line by hand and test the entire sequence.