Have you been searching in AppStore for an application that let you use your iPhone, iPod Touch or iPad as an external harddrive without using WiFi?
With Filetransporter that is possible. Just install Filetransporter, connect your iDevice to iTunes, go to Applications, scroll down to Filesharing and add files to Filetransporter. Then you can move the files to another computer, open iTunes again and copy the files to the computer.