You need iPod Access, it is and nice app that lets you get music of iPods, in this case it lets you manage iPod Touch and iPhone software to get the music off †he device. Google iPod access and you will be able to download the app, although you will need to buy the license to enable all of its features. Once you have the music just transfer the music to the HD. Senuti is great, but if I´m not wrong it is not able to recognize iPods touch or iPhones. And if you don´t register iPod Acces it will only let you take 5 songs at a time so it is kind of annoying.
Answer to: moving music off a iPod Touch and onto hard drive