How to sync the iPhone with two computers (two sets of iTunes media)

Add this to the still small but burgeoning group of useful, native iPhone applications. One frequently lamented iPhone omission is the inability to synchronize media with two separate computers, containing two separate iTunes libraries. If you already have iTunes media (music, video) synchronized from one computer, hooking the iPhone up to another computer will only give you the option to overwrite all existing media with what's stored on that system.

SwapTunes is a small binary that, when run, simply creates and switches to a new iTunes library on the iPhone itself. This new library can be synchronized with a different system. You can then run SwapTunes again to switch back and forth between the two libraries. The process works like this:

1. Sync your iPhone with the first system, acquiring the appropriate media
2. Disconnect your iPhone
3. Run the SwapTunes application (from your iPhone)
4. Go check the iPod application on the iPhone, and notice that it displays "No Content"
5. Connect your iPhone to the second system and sync it, acquiring the second set of media.
6. Run the SwapTunes application again when you want to switch back to the media acquired from the first system.

SwapTunes can be easily downloaded and installed through Installer.app (under Utilities). For instruction on using Installer.app, see our guide.