My understanding of Lithium Ion batteries is that they do not have "memory" like older batteries. Most of what I know I learned from information concerning my iPod. The following information is from Apple's website (http://www.apple.com/batteries/)
"Lithium-ion batteries pack in a higher power density than nickel-based batteries. This gives you a longer battery life in a lighter package, as lithium is the lightest metal. You can also recharge a lithium-ion battery whenever convenient, without the full charge or discharge cycle necessary to keep nickel-based batteries at peak performance. (Over time, crystals build up in nickel-based batteries and prevent you from charging them completely, necessitating an inconvenient full discharge.)"
"For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Be sure to go through at least one charge cycle per month."
"A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could listen to your iPod for a few hours one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle."
It is the charge cycles that keep the battery working correctly. It doesn't matter if you do it all at once or a little here and there. Related to this, it is my understanding that the initial charge makes no difference, though Apple does recommend a full charge before using the iPod. I think this policy is more to prevent new users from complaining about a new iPod's battery life than any physical effect on the battery's long-term life.
