Apps are the applications that developers create for the iPhone and iPod touch. Anyone can make an app all they have to do is download the developers kit, and know how to program it (it’s probably a good idea to have a device to test on too).
The variety of programs out there is amazing - from games, to foreign language dictionaries, nautical navigation apps. If you can think of it someone else probably already has.
All you really need is one good idea, and you can make a pretty penny, selling the app.
Savonix’s uplink software would make a cool app. Input parameters for a room, and drag and drop icons to see what the room would look like before you rearrange the whole thing. One could even upload images of the room if they wanted, and reference them, and store their data.