If iPhone users who need an extra boost of power through out the day would like something less clumsy, you can go ahead and pick up the Incase Power Slider battery case for iPhone 3G. This battery not only gives you a much needed power boost, but it also protects from the everyday wear and tear on your iPhone.

The Incase Power Slider has a built-in 1,220mAh rechargeable battery that will recharge your iPhone 3G without the need for cables. Incase claims that this battery will deliver up to 330hrs extra standby time, up to 26hrs audio playback, up to 5hrs 3G talktime (or double that in 2G talktime), 7hrs video or up to 5hrs 3G web browsing (or 6hrs connecting via WiFi).

This battery also has an LED charge display similar to that of the MacBook Pro batteries. If your going to pick one of these up your wont have to wait much longer. They are going to be on sale starting November 28th for around $100.  This may be a bit more than a typical backup battery, but it holds more of a charge.

[Via SlashGear]