The P-Flip is a foldable power dock available in five different colors. For $55, it acts as both a backup battery and a dock for your iPhone or iPod touch. The backup battery has a 2000-mAh capacity, which should give you about two full charges.
So it should add about 8 hours of talk, 15 hours of gaming, or 80 hours of music. This should help you stay juiced up and get the most out of your iPhone or iPod touch.