throw a towel on the bar (to thicken the grip) and do some pulling exercises like deadlifts and pull ups. you can also use something called fatgrips...they'll run you about 30 bucks. working with a thicker grip will increase your grip and forearm strength. farmers walks are also great exercises for that.
search for a thread started by iniquity about the cambered grip doing pushups...that'll build up wrist and forearm strength too.