I have been using a Mophie Juice Pack for my original iPhone for a long time now. The device gives me much more call time and lets me play games and music longer before the phone is dead. Using the Juice Pack I get roughly twice the run time on my iPhone.

Mophie has announced a new version of the Juice Pack for the iPod touch 2G that promises significantly more run time when used. The touch 2G Juice Pack fits onto the iPod like a case and provides up to 72 more hours of playback for audio and up to 7 hours more for video.