iTunes is the main app for controlling iOS devices on your computer. But when you're not near the computer that contains all your music and need to copy music from that device, iTunes can't help. Even manually managing an iOS device on another computer doesn't allow for exporting files.
The solution is very simple - use Sharepod: a free program that can access any iOS device. I recently replaced my iPod 3 Gen and used Sharepod to export my entire library off my old iPod to reload through a new computer. Here's a step by step guide:
1. Connect the device to your computer with the USB cable. Sharepod will load the device.
2.Select the files you want to export and click "Copy to computer."
Sharepod gives you options of where to save and the formatting of the folders for music.
3. After completing your options, click "Ok" and Sharepod will begin exporting the files. Export times vary on the size of the library, but with patience you will have your entire library available on your computer.
Sharepod is a great free tool for music and video backups and much simpler than iTunes! I tested it with my iPod Touch 3rd Generation, iPad 1, iPad 2, and iPhone 4S and after the computer installs the initial driver, music and video files are accessible. Sharepod can't export apps, but it can export a selection of files or backup entire music libraries.