During the archery constest, in one scene Prince John has a ring on his right paw with no jewel, then all of a sudden the jewel appears. a few scenes later he has three rings on that paw, and later he has no rings at all.
When Robin Hood and all of the villagers are having the party and singing and dancing, look closely at the dance, it's from Snow White. Some of the villagers are the dwarfs and Maid Marion is Snow White. Also, when Little John is dancing it's from The Jungle Book.