+1 for Llama. For starters it's free, and the author blogs about and updates the app frequently. One thing I do is turn off the Bluetooth, WiFi, 3G data, account sync and GPS between 12 midnight and 6:30AM. All calls and texts still work during this period, but it saves my battery a ton.I really like Llama - Location Profiles, really customizable. For instance I have several profiles where if im low on battery, it will shut off wifi, gps, data and turn brightness down. Also another profile setup where if my phone is connect to my BT car, it will turn on GPS, otherwise turn GPS off. Very flexible in regards to what you can program and very simple to use.