Same problem here, photo sync used to work fine, stopped all of a sudden. I wanted to sync before the 1.0.2 update just in case, and I had about 200 photos outstanding. Plugged in phone, not recognized in iPhoto or image capture. Rebooted mac (G5 dual), reset iPhone, plugged in again, nothing. There were a couple of timeouts on the USB bus in the log that looked suspicious.
I was now at the "grasping at straws" stage, so I grabbed the USB cable that was included in the iPhone box and tried that (I had been using the USB cable that came with an iPod). This was -really- grasping at straws and really hoping for magic, since the phone with the other cable was working fine syncing with iTunes....just not the photos.
So unplugged the old cable, used the new one, and it worked. Freaky. To double-verify, I went back to the iPod cable, and it also worked now. Double freaky.
So, who knows. But it might be worth a shot to try the original cable if you're using a different one. Switching USB ports maybe would help as well? Or just plug it in, leave it for a few seconds, and then unplug both ends of the cable and plug it back. Nothing makes much sense, but these activities apparently fixed it for me.