New day, new tweak in Cydia: iControl. This tweak automatically manages the state of your WiFi, Bluetooth, 3G and 2G radios to maximize the battery life of your iPhone. It also save battery by allowing you to designate apps that iControl should kill after you lock your iPhone
Once you have configured your preferences ( i.e you want your WiFi, Bluetooth and/or 3G ON, only when your phone is unlocked or charging ), iControl will make it happen every time you unlock and lock your phone. By ensuring that, you use only the fastest battery sucking radios like 3G and Bluetooth, when you need them.
NOTE: iOS4+ only
NOTE: includes SBSettings toggle
iControl is available for $4.99 in Cydia Store via BigBoss repo