Let’s face it, there is a lot of personal information that we cram into our iDevices. Contacts, notes, social networking accounts, email, photos, you name it. All of which could potentially be hijacked or viewed from someone who manages to spend a few seconds on your iDevice. It happens; a friend who is perhaps interested in your iPhone asks if he can take a look, but your hesitant to hand it over, at the risk of leaving something available for him/her to accidentally open. But what if you could have the confidence in knowing that what you want to be kept private, will indeed stay private.
You Can Grab This Tweak From Cydia For 2.00 $ There are a lot ways by which you can get it for free (Google is Your Friend).
It does Work uptill iOS 4.3.1 (Maybe 4.3.2 ; Try for Yourself).