As an owner of two "MacBook Pro (late 2008)" units (gotta love the Apple official model title), I've experienced an overheating issue quite frequently. It's becoming known as "hot laptop in bag, syndrome, v2". Here's a quick tour of the problem with a bunch of the news articles published in just the last few days.
There's a quick description of the problem by Gizmodo then, the actual thread on the Apple site, followed by a suggestion to use SmartSleep to turn on Hibernate mode only, or reset your SMC, or reset your PRAM, or actually get a firmware fix. Take your pick.
And if you don't find that enough, go ahead and check out the electron microscope pictures and spectrograph of the bump composition that says NVidia is not being transparent about the failing video chip problem.
Does this just make you want to run out and buy one of these new units?
Lest you think I'm switching back to PCs, these Macs are still way better than my last Dell D600 that required 4 complete overhauls for failed components in a 90 day period.