Can't charge? Can't sync? USB port/connection not working? See here:
I see that there are lots of posts/threads that share the same bloody problem that I had a few weeks ago which was driving me nuts and up every wall in my flat.
If you can't sync w/iTunes, can't charge or just have a USB connection problem and you don't hear that connecting "chirp" sound when you plug or dock your iPhone (make sure vibrate mode is off), see my original link below:
http://www.hackint0sh.org/forum/showthread.php?t=12431