Oops, the edit doesn't bump the post up to the list of unread topics, I just now saw it.
If you want to transfer everything, you'll need about 3 DVD-Rs. On the Mac, in iTunes click File->Library->Backup to Disc. You could use CDs but it would take a whole hell of a lot. Like 18.
Once you are done burning the DVDs, open iTunes on the PC, and put in the first disc. iTunes should ask you if you want to restore from the disc, click restore, and wait, swapping discs as it asks for the next one.
That method keeps everything intact, including playlists and ratings.
If you JUST want the songs, and have a USB HDD or large enough thumb drive, you could just manually copy the songs to it. On the Mac they should be under /Users/dpm/Music/iTunes where dpm is whatever your username on the Mac is.
Once you have them on the USB drive, just connect it to your PC, open iTunes, and drag and drop the folder onto the iTunes window and it should import everything, though you'll lose any extra data.