A bigger hammer is the answer.... or....


remove all the lug nuts.
slowly lower the jack.
the camber change as the wheel is lowered should help pry it off.
DON'T LOWER IT TOO FAR.
just get some weight on it, with the lugs removed, then beat and bang on it.

or...

Jack it up, so the wheel is in the air.
sit down and 'kick it like a donkey'....
yup.. sounds stupid.. but it's that or a bigger hammer.


clean off your hubs and grease them really lightly...
then it won't happen again.

btw... everything mentioned above... is at your own risk.