So I have all my music and playlists in windows media player and originally transferred them to my pre using mass storage mode. However, as others have noted, the playlists themselves do not transfer. I intially solved this by saving the WMP playlists as .m3u files. This got them to transfer but the m3 tag data got screwed up (the title of each song would be the actual file name, eg "03 Beat_It.mp3").

My solution was to use both WMP and Itunes with a program I forgot I used to use called musicbridge. Musicbridge syncs windows media player with itunes, including playlists. So I imported my music into itunes and with one button got correctly formatted playlists imported from WMP. The nice thing about this is that you don't really have to use itunes except to sync the pre since musicdock will import any playlist changes you make in WMP to itunes.

So a bit of a kludgy solution, but if you were having the annoyance I was, you may find it useful.