Apple has posted new section their battery technology.
"Paying attention to just a few common sense pointers will pay off with a longer battery lifespan and battery life for your iPod. The most important thing is to keep your iPod out of the sun or a hot car (even the glove box). Heat will degrade your battery’s performance the most."
There's a great page on the iPod and another on laptop power useage.
The highlights:
• Update to the Latest Software
• Use iPod Regularly
• Hold and Pause
• Minimize Backlight Time
• Turn off Equalizer
• Use Compressed Songs