You'll have to wait

Sorry dude Battery Control is what you're looking for. But its for 3.x only. I was in same boat as you. Downgraded my 3g. Now its sweet.
You can still hit thanks

Peace Brother !

Enjoy it while you can
---EDIT---
iOS4 device need winterboard to do this

Using photoshop you can whip up a few blank png and theme it or even easier in cydia search for battery hide or something