Auto Transfer everything into iTunes

The easiest way to transfer all music and playlists into iTunes on your computer is to perform an Auto Transfer which will do it all for you in a single transfer. This will also include information about your favorite tracks (the play counts and star ratings for each one).  

To Auto Transfer everything, just click on the drop-down menu in the lower right corner and choose Auto Transfer. Then, in the confirmation window, click on Start Auto Transfer. 

Here's an additional tutorial:

How to transfer music from iPad, iPod, or iPhone to iTunes