To use File Sharing, you'll need a computer on the same Wi-Fi network as your iPhone/iPod touch. In the "Settings" screen, turn on the "File Sharing" switch, then open the http address shown below the switch in your desktop web browser (e.g. Firefox, Safari, Internet Explorer, etc.). Or, if you prefer to use an FTP client (e.g. FileZilla, Cyberduck, Transmit, etc.), use the provided ftp address. Once connected, you can transfer files between your computer and the iPhone/iPod touch.

If your iPhone/iPod touch is running iOS 4.0 or above, you can transfer files using iTunes USB File Sharing. Connect your device with a USB cable and launch iTunes, select your device, you should see the "File Sharing" section under "Apps" tab. Select "Downloads" from the list. All of your files are listed and you can drag and drop them right out of iTunes.