It's not going to help your battery life issues, but if you want to break free of Apple's checks and balances that prevent you from running any old app on your new phone, you'll be happy to hear that the iPhone Dev-Team is already demonstrating a preliminary jailbreak for the iPhone 4S and iPad 2.
Based on a tweet from MuscleNerd, iClarified is reporting that while the Dev-Team has found a way to get Cydia to run on both devices, the jailbreak is still "very preliminary" and "Huge missing pieces prevent public release. LOTS of work left...".
So it's no where near ready for primetime at this point, but enough to get people excited, and more than enough to put another burr under Apple's saddle. I've also included a video that both demonstrates Cydia successfully loading on an iPad 2, and that techno music can improve even the most mundane clip.