Magic Find does work on bosses, including Act Bosses. Whether it would or wouldn't changed several times during the beta, but in the final version of v1.10 it does work.--- Taken from Diabloii.net

Looks as though blizzard has fooled us. I appologize for my wrongfull post. I was going by information supplied by another user on the forums. I guess ill stop listening to everyone else and do my own tests.