are you sure you picked the correct folder and not say, your entire home folder?
Try experimenting with folders of pictures, where there are much fewer pictures to sync.
It shouldn't take too long to sync, though the first one is always going to take awhile.
Don't rule out directory damage on your mac. A damaged directory entry in your pictures folder could be stumping itunes as its trying to calculate space before syncing.
You can also open activity monitor in Utilities folder and click on disk activity to confirm that it's doing hard drive i/o, and also look at how much cpu itunes is consuming, for clues as to what's going on (or NOT going on) behind the scenes.
