How do you get apps on to an iPhone off iTunes?
Sync your iPhone to iTunes on our computer
If the applications are downloaded via iTunes, they will be automatically transfered to the iPhone during synchronization. Otherwise, the apps downloaded via iPhone will be copied and backed up to the iTunes during synchronization. So to transfer the apps to the iPhone, just connect the phone to the iTunes and sync. Click on iphone on the side bar, then apps up the top, then sync apps.