This thread is designed to provide ready answers to the constantly repeated questions regarding the iPod's battery.
Taken from our FAQs here and here
How long can you expect your battery to last?
For more than 500 battery charging cycles (one charging cycle consisting of draining the battery, then recharging it to a full charge) Depending on heavy or lighter use, this battery life span can range from approximately 2 or 3 to 8 or 9 years.
How long should I charge the battery when I take it out of the box?
Charging it for 3 hours before first use is recommended.
How to best charge the battery?
You should recharge it to full charge regularly, before it has an opportunity to fully discharge.
Does the iPod battery have a memory effect?
What is the difference between charging via FireWire or via AC Adapter?
Many experienced owners always recharge using the AC adapter as opposed to recharging from the FireWire port on their computers because it is quicker.
Is the battery meter inaccurate?
Yes. Users have reported that after fully charging the meter shows only half power. This usually normalizes after a few minutes of use. Also, with the meter on empty, you can get hours of playing time. The meter is thus no true indicator of battery power.
If I don't get 8 hours of battery life, is the iPod defective?
Not necessarily. Battery life varies according to use (menu switching) and individualized settings. Doing a battery test will determine your iPod's performance: load the iPod with enough tracks to play for at least 8 hours. Allow the iPod to play the tracks using the standard settings (no EQ, normal volume, etc.) and without accessing it during this time. The iPod should play for 7-8 continuous hours.
Apple's tips on how to get the most out of the battery
Caring for the battery
How to replace the battery for yourself
ipodbattery.com replacement pictures
Apple's battery replacement service for $99
Please feel free to post additional comments (primarily answers) on battery use and charging tips so that all myths can be dispelled!
Edit: please also view ipodbatteryfaq