Tweakers Australia has just posted part one of thier article on Case Cooling. Heres a Snip:

    No doubt many of us have had our computers freeze after hours of playing games, playing your collection of DivX ;) movies or rendering that slick 3D Model in 3D Studio Max. No doubt, you've blamed Microsoft Windows, but is Windows really the problem? (ok, of course the answer is yes, but look deeper) If you looked inside your case, you probably have a whole heap of dust and carpet hair, geeze, maybe even a few cockroaches; do you really think all that stuff in there is doing your computer any good? No, it's not. This article will show you how you can tidy up your case to maximise cool air flowing to your CPU and components, and hot air out of your case. I will also show you how to place certain combinations of fans in their optimal arrangements.