When the Aluminum 12 inch and 17 inch powerbooks first came out a couple of years ago, I immediately bought a 12 inch for myself. A while after I started using it, I started noticing that my powerbook was overheating most of the time. At certain times I couldn’t even rest my hands on it and there was no way that I could rest it on my laps. Now in the beginning I thought that the overheating problem was just with my powerbook. But then I researched online and posted my concerns in a couple of apple forums and it turned out that all powerbooks had the same overheating problem not just mine. I was a bit relieved since there wasn’t any deficiency with my powerbook, but that didn’t solve my overheating problem. However I learnt how to live with it. In the winter it kept me warm but in the summer it was a big hassle since my fingers use to get all sticky on the keyboard.

Anyway I was reading this Link about Apple currently recalling 225,000 batteries it shipped from October 2004 to May 2005 since the batteries were overheating and in some cases becoming hazardous to consumers (such as blowing up). And it was interesting to know how this became a major issue for Apple not just a minor overheating problem. Here’s a link to read more on this.
And here’s another link on the Apple Recall Program.