Ars Technica has a short guide up to treating your iPhone, laptop, and iPod batteries right
. Contrary to popular belief, it seems the best way to wear out a battery before its time isn't spending too many charge cycles-- it's heat. Charge cycles are equivalent to normal wear and tear on batteries-- it's better to charge your batteries up from partial charge rather than let them run all the way out, and then charge them fully. But heat is a much bigger factor, and considering that most laptops (or "notebooks," as Apple likes to say) run hot
, batteries lose their capacity comparatively fast.
The best way to store a battery, says Ars, is partially charged and in the fridge. In fact, one of their batteries still had a 95% charge after 2.5 years, just because most of that time was spent in about 40 degree temperatures at half charge.
Of course, I buy batteries not to keep them in the fridge, but to use them, so I'd like to see (and have seen, don't get me wrong) progress in lifespan and capacity rather than a battery next to my Guinness in the fridge. But if squeezing every little bit of your battery counts, it sounds like you can't go wrong by being cool.