Available now from Neoos...

The coolest way to check out your remaining battery power!

The remaining battery power is visualized as a green, gravity sensitive fluid. Turn your device to any side and watch the green fluid flow.

A percentage display and a status line (which reads "charging", "unplugged" or "full") have been added for your convenience.

Please note that the iPhone SDK only supports battery status reporting in increments of 5%.

ENJOY!