^+1
I agree with chookman. While the site I linked will help you overclock, it might not give all the information you need to understand what you are really doing, especially with voltages (both to CPU and memory) and timing settings.
If you do go head on, just do small increments, and test. Don't just do a huge adjustment.
Oh, find out how to reset your CMOS as well. It could prove very useful.