Mine were stuck pretty good as well. I tried some penetrant but it still wouldn't come off. Since I was changing the rotors as well I just beat on them with a hammer.
<img src='http://www.geocities.com/royb9t8/MY_BMW_2.jpg' border='0' alt='user posted image' />
<span style='color:blue'>My ass may be dumb, but I ain't no dumb ass!</span>