The guys at PC Watch got their hands on a PS3 and promptly took it apart. When I say took it apart, I mean they went as far as removing the heatspreader from the GPU. Check it out, there are almost two dozen pictures of the whole process, I snagged this one to get you started:
http://pc.watch.impress.co.jp/docs/2006/1111/ps3.htm
http://pc.watch.impress.co.jp/docs/2006/1111/ps3.htm