Actually, Ampharos can learn Outrage via Move Tutor. This is only in Gen 5 and below, you'll have to wait until PokeBank comes out so that you can trade an Ampharos that knows Outrage to your X/Y game.
I actually wouldn't teach Ampharos Outrage anyway, because of its low Attack stat even in Mega Evolution, but that's just my opinion. :P
Hope this helped. :D