In the southeast part of Pastoria City, there is a fat man in a house. In exchange for a Heart Scale, he'll teach your Pokemon a move it had forgotten already.
On Route 210, there's a woman who teaches Draco Meteor to any Dragon-type Pokemon. She can be found in her house at the northern part of Route 210. That house, with the 6 on it, is Grandma Wilma's house, who teaches you Draco Meteor.
On Route 228, there's a tutor who teaches moves to any of the 12 starter Pokemon from the various games. The moves that he teaches are: Blast Burn, Frenzy Plant, and Hydro Cannon.
Diamond and Pearl move tutors