Building a Liquid Cooling System

Well, you'll need these.

CPU waterblock
GPU block (If you're planning on it)
Northbridge block (you really don't need it, it is a novelty at best. Just get a good Air Cooler if your's is passive or loud)
Pump (Either Danger Den or Swiftecs $75ish pump. They are the same)
Resivoir (or T-line, take your pick)
Tubing (I'd recommend Tygon, 1/2 inch)
Radiator (If only CPU block, 1 or 2 fan rad. CPU+GPU: 2fan, and a 1 fan)
Coolant (save yourself some money, and just get an additive that you mix into distilled water. If you don't get an all in one kind, you will need a Corrosion inhibitor, Algae inhibitor, and also something to absorb more heat.)
Clamps (You can pick up some "worm drive" tube clamps at your local hardware store.)

Swiftec, and Danger Den are both great brands.

You can find most, if not all of this at:
www.petrastech.com
www.crazypc.com
(both respectable sellers).

Your loop should go: Pump-->CPU-->Rad(1)-->(GPU if you want it)-->(IF you got a GPU block) Rad(2))-->Resivoir(or T-line)-->back to pump.

Definatly.
Also, try going to www.xtremesystems.com, and go to watercooling

Thanks for all the help, guys...

But my question is, is it worth it? Right now I'm using a Scythe Infinity CPU Cooler, and its working pretty good, being that it's cooling a P4 at the moment. But my fans are LOUD. My case (Thermaltake Shark) supports Liquid Cooling, so I thought I may put it to use, lol. Only problem is that the holes in the back are 3/8, i think, but nothing a drill can't handle.

Also, don't you have to replace the coolant every month or so?

Also², would be a bad idea to move a computer with a liquid cooling system in it? Would it like leak water everywhere? 8O