For those who have upgraded or uses iOS5 and having problems with your battery, then you might stumbled with the same bug everyone experienced. Apple engineers are working to fix the bug, but meanwhile, you might be able to solve this by following these steps (taken from FreakGeeks)
Step 1: First of all, head over to Settings.app on your device, then Location Services and finally tap on System Services. (Settings > Location Services > System Services)
Step 2: On that page, at the bottom you will get a toggle switch to turn OFF/ON “Status Bar Icon.” Switch ON that toggle to test, is something going on your device? Definitely, something going on!
Step 3: Now, heads over to the main part of the tip, at the same page you will get “Setting Time Zone,” all you have to do is a toggle it OFF, and check the status bar for the icon, is it still there? Well not!
Step 4: That’s it! Now enjoy the new battery life of your device on iOS 5.
That's it. Piece a cake right? Yup.. the bug was due to Apple software tried to keep tracking the location of the device for the auto time zone setting, which cause continuously using the GPS service of the device, and considerably it draining device battery. By turning off the feature, hopefully you will regain your long lasting battery