Can you tell the fix you did..
I would like to do that.
You'll need a Torx, security bit (I forget the size). Remove the warranty sticker from the side of the PS3 which is over part of one of the rubber feet. Then gently pull the foot off, you'll find the Torx screw under there. After you remove that the top will slide to the side a bit and lift off. From there it'll be standard Phillips screws for the rest of the disassembly.
I can't remember all the details. You can find disassembly instructions online anyway. But you start with removing the screws which have arrows pointing at them. Be careful with the first few which hold the case in place, they are going into plastic posts, if they're stuck you'll break the post off.
Just continue disassembling until you get to the part where you can separate the fan from the motherboard.
You'll want a can of compressed air to blow out all the dust. Also you'll need something to remove the old thermal wax. I use ArctiClean. It's just a two step cleaner, the first is a citrus degreaser, and the second is alcohol to clean the remnants of the first. You'll see how badly the original compound has migrated from where it is supposed to be to all around the Cell and video chips. Just use the degreaser to dissolve all of it, and then the alcohol to get it all squeaky clean. Finally, replace the crappy wax with one of the new, high-tech compounds. I used ArcticSilver 5, but there are actually better products than that available now. Follow the application instructions for what ever you use. Most of the time that's to put a small, smooth glob in the center of the chip. The pressure of clamping down the heatsink will spread it out evenly, and without air pockets which can form when trying to cover the whole surface evenly.
Reassembly in the opposite order of assembly.
It is a little harder than building a computer, but not much, and I'd say easier than dis/re-assembling a laptop.