well in terms of cpu OCing there is now program for it.
Its all in your bios
My favorite guide out there, iv been now treating it as my relgion.
In terms of GPU OCing there is a program....sorta
You can download either rivatuner, Coolbits, powerstrip, or ATI tool.
I reccomend riva tuner and ATI tool.
Im not going to explain how to in this post but its fairley easy Im sure a quick google search should help you
What kind of water cooling, custom? Danger Den?