I've been using this for a while and it really is nice. It plugs a gap between my phone and my Mac.
Dare I say Nokia is finally playing properly with Apple? Well, I don't know, but I do know that Nokia phones are no longer second class citizens in the Mac universe. This is indeed a step in the right direction. Together with iSync, you can now transfer contacts, calendar, photos, videos, and music between your dearly paid for Mac and your dearly paid for Nokia phone (alas, only Nseries phones).*
This app makes it easier to transfer music from iTunes to your phone. It also makes it easier to get photos and videos into iPhoto (and back). It doesn't work on DRM'd (hiss, Apple FairPlay) music and videos, but free stuff will be properly converted to play on your device (assuming you have the right device, yada yada). UPDATE [10jun]: It can also transfer iTunes Plus (purchased but not DRMed music). See Nokia Media Transfer FAQ on Music for more info.
Yes, you can have your cake and eat it!
The Nokia Media Transfer application enables you to transfer pictures, videos, podcasts, music, and files between your Nokia mobile device and your Mac.
*ah, but I also want to synch my to-dos and notes and bookmarks, too. sigh.