I'd like to throw in one more idea for everyone suffering this. It may not be the answer for you, but it was for me. Like others, I found my phone stuck in the last step of the sync. In my case, it said it was "artwork", but I know others have likely been stuck in some other "last step".
For me, after reading this thread and some others, I decided to simply tell it not to sync photos. I disconnected, reconnected, and bang, it synced to completion. Maybe others will need to tell it not to sync books, or podcasts, or videos, whatever. But give it a try.
For those not familiar with how to tell it "not to synch photos", for instance, in the itunes interface, when you've plugged in your phone, click on the phone in the "devices" area of the left tree structure. (If you don't see it there, and your phone is connected, try disconnecting and reconnecting it till it appears.) Then choose photos from the list of options that appear above the picture of your phone (or click whatever you want to try not to have it sync.) Uncheck the option now shown to "sync" whatever you selected. Click the apply button at the bottom.
In my case, I did that while it was "stuck syncing". Of course, it didn't "solve the problem" then. I had to go ahead and disconnect it (click the icon next to the phone in the "devices" tree), adn accept its warning that it was not finished. Of course, I'd usually never do that (or just yank the phone from the connection) while syncing, but in this case, I seemed to have no other recourse.
So I unplugged it, and reconnected (needed to do it a couple of times before it appeared in itunes in "devices", but that happens fairly often), and then it proceeded to sync. And it DID finish. Hurrah!
Hope that may help someone else.