Would MacDrive allow you to read the iTunes Music Library file?
What I mean is, you have iTunes on the Windows partition, and instead of copying music over (I have a lot of music) you read the Library file iTunes produces so you can read the music files stored on the OS X partition...
Steve
My guess is that since you are running iTunes in Windows, you can point your directory to the folder in OS Xs partition, but you can't use the iTunes library file, windows will create its own for that version of the app, meaning that you won't have any playlists in windows unless you create them there as well. In addition to which I'm pretty sure, while windows will see the folder, subfolders, etc, you would still have to add to library any new music each time you access the windows partition that was added to the OS X iTunes since the last time you used windows. iTunes won't detect changes and add to the library, especially since tracks can be removed from a libary w/o deleting them. There is a way in OS X for multiple users sharing iTunes/iPhoto libraries to each update and always have access to the same data, with libraries, playlists, etc updated from eachothers changes, but I doubt that would work across platforms.