If you jailbreak, the percentage batter meter is just a switch away with the free SBSettings app. If you're not interested in doing that, I believe it's just a

If you jailbreak, the percentage batter meter is just a switch away with the free SBSettings app. If you're not interested in doing that, I believe it's just a simple .plist change and reboot (or respring). However, you can also enable multitasking/wallpaper if you jailbreak.