To "hack" the eDGe, you need to be able to root it. As far as I know, no one has successfully done that. And since I'm pretty sure that doing so would violate your warranty, I'd strongly recommend against it.

Hopefully, when the SDK is released later this year, there will be greater options. But for the time being, all you can do to conserve battery power is the obvious: brightness, turn off wifi when not being used, etc.

If you're noticing that the speed is noticeably slower than it was originally, then you probably have a lot of third-party apps running. Either uninstall those and/or download a startup manager so that you can tweak which ones load by default.