http://www.pocketlegends.com/ Pocket Legends is a 3D MMO For the Ipod/Ipad/Android. The graphics are decent, the lag is low and the fun is high. Player on the Ipad, Ipod, and Android are all put on the same server so you can play on the same account from any device.
The game almost based soley around raids and quest. (completed during raids) The first few levels are a little boring, but once you move up to the raids its very fun. And don't worry, if you try the game, any class you pick is good in someway. Also you can just create a new character with a different class.
The dowload is free, and so are the first few maps.
So, get on iTunes and try it out!