Has a sync somehow gone terribly wrong and you've lost your favorite paid application for your iPhone or iPod touch? Well, if you didn't have a backup of it in your iTunes library, fear not. Apple has designed the App Store to allow for re-downloading purchased applications.
All you have to do is navigate to the application that you originally bought in the App Store and tap "Buy." You will have to enter your password, and the App Store will return you to your home screen where it displays a message saying that you've already bought this application and are entitled to an additional free download. After you tap "OK," your app will begin downloading.
Now you don't have to fret about losing your favorite iPhone or iPod touch application.