If you share your iPhone, iPad or iPod touch with someone else, or have multiple accounts, you might find it useful to be able to install an app twice — or maybe even three times. If so, iFans forum member abdallah has come to your rescue, with a tutorial on the discussion forums that outlines how to install an app more than once.
You will need a jailbroken iOS device and a plist editor such as iFunBox for Mac and PC, or iFile directly from Cydia. The rest of the steps are outlined in the tutorial thread, and these instructions should be followed at your own risk. There are risks that can be encountered by manually tampering with iOS software.