Originally it had to be the OEM Apple adapter, but I believe some of the newer third party cables work too - it just took longer to copy than normal.
Look for the ones that are able to sync with a PC and it should work. The charge only ones (which was all the original ones) didn't sync as it needed an extra chip in the cable which they didn't copy.
I'd get the Apple one, though, and avoid any potential messing about.