I have the OTA and i have been having some battery issues.. so i looked for an app.. and found JuiceDefender. It works AMAZING

It cuts off your 3g whenever you put your phone to sleep but it turns it on for 1 min for every 15 that it's off to get updates and if apps need to access the internet.
It also realizes when you are using pandora or any other app that needs 3g when the screen is off so that you can listen to it when the screen is off.
It saves so much battery!

It also works with wifi so that it only turns wifi on when you are near a saved network.

You can add sleep periods to auto turn off 3g/wifi whenever you want (aka sleeping)

I love it and it saves me a lot of battery.