Although lots of clients were expecting iOS 5.0.1 to fix the battery problem, Apple didn’t incorporate the fix in this release. Nevertheless, the beta versions of upcoming iOS 5.1 have revealed that Apple will fix battery drainage issues in the next releases, much to the relief of the users.
But until then, people at insanely.com have found out a solution to solve this existing battery problem. A tweak, battery fix for iOS 5, has been released to deal with the issue. However, the problem with it is that the tweak is only available to the members at insanely.com. However, a membership can be acquired only for $4.99. It is to be noted that the tweak is yet to be fully tested as per jailbreaking teams.
Remember that to get this tweak working, the device needs to be jailbroken first. Here is the procedure to jailbreak your device step-by-step using Greenpois0n Absinthe.
(Information from PWNAGE TOOL)