Also, note that there's a good chance you will have to replace the drums as well. The brake shoe surface can be resurfaced, but the armature surface -- where the magnet rubs against -- cannot. I called lots of machine shops to find out. So if you've never done so, you can count on replacing those too. If you don't, your magnet may wear unevenly, and you may also have decreased braking performance because the magnet is not in full contact with the drum.
I just cleaned/repacked my bearings a few days ago....my least favorite job. It was less unpleasant this time as I tried out my new Lisle bearing packer. No grease gun required, and you force grease into the bearing (from the tapered/smaller end) until it comes out the other end.
http://www.amazon.com/Lisle-34550-Ha.../dp/B0002NYDYO
Dave