The drum is actually ready to come off so long as the big nut has been removed. The trouble is, the bearing inner will have rusted to the stub axle, so get some WD40 in there and pull and rotate the drum to work it loose. You'll find that the drum will be reluctant because of the wear lip ground into it by the brake shoes, and the worst scenario is that you'll need a slide hammer to shift it. Its best to get a garage to press out the old bearing and pop in a new one for you too.
John
May 2009