Sometimes when I carry my N800 in a pocket, it gets very warm (hot) along the top edge. Any idea why? This seems like it could have a detrimental effect on the battery life.

I've had that happen to me just the once and the battery had become flat - wouldn't turn on, even though it had been on standby for 3 hours max, from a full charge.

I initially suspected a short circuit somewhere, but I guess it was just a rogue process maxing out the CPU or something.

Put a battery in your pocket for an hour and see what happens. It gets red hot. The same might be true for the N800. Did it happen with it completely off? My guess is that the body heat from you comes in contact with the N800 and somehow warms that battery. If it happened when its off...you won't be able to pocket it anymore.

I've had a couple of instances where the top has gotten pretty warm. The first time I fixed it by remove my Maemo Mapper cache from the metacrawler path. The second time I fixed it by reducing the tension at the base of the device.