How to: Move an iTunes library from PC to Mac and back

If you've got both PCs and Macs running side-by-side, either at work or at home, you've likely banged your head against your keyboard in frustration when trying to move your iTunes library from one platform to another. Sure, you could just copy the music files over and re-import them, but that requires leaving behind your beloved playlists and ratings. Well, the good news is that inter-platform iTunes transferring can be done, but it requires a little work on your end.