copy itunes from pc to mac the easy way
1) If you haven't yet, run and quit iTunes on your Mac.
2) Open the ~/Music folder on your Mac (Music in the sidebar) and proceed to open the iTunes folder.
3) Throw away the "iTunes Library", "iTunes Music Library.xml" and the "iTunes Music" folder.
4) Copy the "iTunes Music" folder from your PC into the iTunes folder.
5) Copy the "iTunes Music Library.xml" from your PC onto your Mac's desktop.
6) Run iTunes and select Import from the File menu. Select the "iTunes Music Library.xml" from your deskop.
7) Your songs should be correctly transfered.
I don't take any credit for the originality of this series of steps. I forget where I grabbed it from, but it works and is very simple. It should keep all play counts, ratings and all of that.