What OS do you have? I think I have a guide in my email (which is blocked at work) for setting up with Win7 Media Center. It's pretty user friendly, so you probably don't even need a guide for that. However, if you're running a different OS, then having a guide for MediaPortal, XMBC, etc. is very helpful.
What are you connecting your computer to: TV, receiver, or both? If it's a straight HDMI-to-HDMI connection between the computer and a TV or receiver, then that should be pretty simple. If you need to run HDMI to the TV and then digital audio to a receiver, then that gets a little more complicated.