i wanted to know the same a few months ago, no windsurf i could find, but catamaraned off palm cove. but somewhere just north between cairns and palm cove, yorkeys knob, was supposed to "kiteboard heaven", didn't see it but a chance there.
BUT DONT MISS ...... CABLESKI i.e. waveboard around a lake on a looped cable on pylons, I rode the kneeboard, wakeboard, tiny surfboardy thing, waterskis and monoski www.cableskicairns.com.au