iExplorer lets you easily transfer music from any iPhone, iPod or iPad to a Mac or PC computer and iTunes. You can search for and preview particular songs then copy them to iTunes with the touch of a button or with drag and drop. Looking to transfer more than just a few tracks? With one click, iExplorer lets you instantly rebuild entire playlists or use the Auto Transfer feature and copy everything from your device to iTunes.

http://www.macroplant.com/iexplorer/