iTunes is a little trickier than iPhoto and I learned the hard way. First you want to go back into your users folder and copy the entire iTunes library to your new drive. Once again, this can take time.
Once that is complete open iTunes while hold the "Option" key and "Shift" key at the same time. Notice the extra key for iTunes. The same type of window asking what you want to do will pop up as it did for iPhoto. Select the option to choose your library.
Yet again iTunes gets a little tricky. iPhoto stores all of you data and photos and movies in its library. iTunes does not. iTunes stores the media apart from the library. However, it is still the "iTunes Library" file you are looking for inside the iTunes folder.
DO NOT DO WHAT I DID AND change the media folder location in the iTunes preferences. I did that before I learned the key command. Most of my music transferred, but games, app, movies, and more were a mess.
Once you find the library file double click and you are done.
Just like the iPhoto library you'll want to delete the old iTunes folder off your computer in time. For now keep it where it is, just in case.