If you've performed any of the many software hacks available for the iPhone that allow you to load third-party software, you need to be careful if you take your phone in for service. Even if it's something totally unrelated to the software, such as something wrong with the iPhone battery, camera, or touch screen, they will not fix it if you have made software modifications. This policy is totally ridiculous, but it's the way things are. If you need take your iPhone in for service, make sure that you perform a complete software reset so that they can't tell that you have made modifications.