I just upgraded to Snow Leopard and freshly jailbroke my iPhone to 3.1.2. Everything works fine except syncing photos. iTunes copies music, movies and apps to iPhone and seem to endlessly say "syncing my iPhone". During this time cpu usage also shoot up. I tried unchecking photos and sync and it worked wonderfully. So why am I unable to sync Photos to iPhone
Here is a screenshot for ref :
It doesn't matter the number of photos you are syncing. May be your itune is not working. Try re-installing the application. Sometimes it works slow if your photos are too big in size or of high quality.