iTunes stopped syncing with iPhone

Same thing has happened to me!

More facts to throw into the mix:
1) This is happening with two iPhones, neither of which will sync, charge or show up in the Finder window on my Macbook. I hadn't checked System Profiler before, but I do now see the iPhone listed there (serial number doesn't match, though, which is weird).
2) Both iPhones, however, show up successfully when connected to another computer.
3) If I connect other iPods to my Macbook, iTunes sees them just fine, sync works, they charge, etc.
4) I've switched USB cables and ports, have restarted the iPhones and the Macbook, and still nothing.

Extremely frustrating! Someone please help!

I have been able to resolve the same problem with my iPhone (at least for now, knock on wood). I reinstalled iTunes 9.0.3 on my Macbook. I did NOT uninstall the existing iTunes 9.0.3 before doing this install. This was a suggestion that I received elsewhere. My iPhone now charges and syncs with iTunes on this Macbook. (It doesn't show up as a disk on my Finder (while an iPod does when I connect it), but I really don't care about that.)

Hope this works for you, too!

I did exactly the same thing. Did not delete iTunes, just reinstalled and now iPhone shows up in iTunes window for syncing!