iOwn ($4.99, available here) is a helpful inventory management system that lets you create a detailed list of all your possessions. If you've ever needed to report a loss to insurance, you know the value of having a complete inventory. The app lets you create an unlimited number of locations, containers, and items, then create attributes to describe each item. You can assign up to four images for each item and secure your inventory with a password. Best of all, there's a free online backup, in case you lose your iPhone.