I used this as a guide:
Lifehacker - The First-Timer's Guide to Building a Computer from Scratch - Hardware Installation
I also used another site that I'm looking for but can't find. The manuals that came with your components-especially for case and motherboard-will also serve as a good guide when the online ones aren't quite cutting it. I'll keep looking for you, though.
Edit: Found one of the guides I liked from Maximum PC.
You can find the simpler, quicker guide here:
http://www.maximumpc.com/article/fea..._pc?page=0%2C1
You can find a newer and more thorough guide here:
http://www.maximumpc.com/article/fea...ide?page=0%2C9