A couple important points here
If you're worried about voiding your warranty, don't be. If you have a 60gb ps3 it most likely isn't warrantied. In North America, *new* ps3s come with a one year warranty, and sony refurbs come with a 90 day warranty. Chances are you have no warranty left.
Also, I'd recommend against using a conductive thermal paste like arctic silver 5. It's a highly regarded paste, sure, but I would personally use OCZ freeze or something similar that is non-conductive.
If you feel this seems daunting, don't worry. Taken as a whole it's quite a bit of work to take apart a ps3. However, when broken down into steps it's very doable. I have never taken apart a ps3 before and I did it in under 2 hours from start to finish. Just make sure you have a set of electronic screwdrivers and a fresh tube of paste on hand before starting. This is very doable by anyone who isn't a moron and can follow simple instructions.
If you choose not to do this and have your ps3 die from ylod, don't say I didn't warn you.
Good luck