Mac – transfering itunes library win-> mac – is it possible

Yes, simply coping your entirely iTunes folder to an other computer will do the trick. This assumes all of your media is consolidated within the iTunes Media and iTunes Music folders. iTunes will assist in copying music to the folder and organizing a library if you would like to ensure all the media is portable when it comes time to transfer.

Do not forget to reauthorize the old computer if you are not going to use it regularly in case it crashes and one of your 5 slots is taken up. You can reset things after a lost computer, but it is somewhat time restricted to prevent abuse of that feature.

In iTunes, on your first machine, you will have to go to File|Library|Export Library. This will generate your Library.xml file.
If you take a look in it, you will see for each file all the fields you will find in iTunes (location on HDD, play count, rating, etc...).

Now, on your new machine, after having installed iTunes, you have to go to File|Library|Import Playlists (not obvious at first as I was looking at an Import Library menu but it doesn't exist) and select the xml file you exported on your first machine.

If you try, as I did first, to edit the xml file and overwrite the newly created one, when launching iTunes, it will delete it and create again an empty new one. You have to go through this Export/Import process (which is quite quick).

PS: you may have to edit the xml file anyway before importing, if the paths to the music files changed from your initial machine. For example, I upgraded from WinXP to Win7. As the user folder path changed, I then had to edit the paths c:\users and documents\myuser\My Documents\My music to c:\users\myuser\Music, or something like that, I don't remember exactly.

PPS: Always keep your exported xml file untouched somewhere until you have everything OK on your new machine...