My 8320 won't sync contacts wirelessly, although e-mail and calendar are working fine. I went to the BB support site, which told me to open options in the Address Book and set wireless sync to "yes", but the trouble is that there is no option to turn wireless sync on or off

So, any ideas?

Setup:

8320
4.2.2.180
Outlook 2003
BES (not sure the version number)

Are you using an exchange host? If so, they should be able to provide you with support.