Did you know you could make your own custom iPhone vibrations? I just figured this out a few weeks ago when I got my iPhone 4s. The Custom Vibration feature is a part of the iOS 5 update.
How To Create Custom iPhone Vibrations
5. Head back to the main “Settings” area (Not Pictured)
10. Tap “Save” once you are done with your new recording. After you complete this it will appear in the menu next to the other vibrations. Now you can have custom vibrations for when different people call or if you get a text, etc…