A lint brush works great. Or if you don't have one of those, duct tape works the same. Take the duct tape, roll some around your hand (sticky side out), and then go over your clothing with the duct tape. Anywhere you see cat hair, place the duct tape there.
Fabric softener in the final rinse will help the hair release from the clothes, and then the tumbling action of the dryer should knock most of them free where they will be caught in the lint filter. Then you can use a lint-roller to remove what's left. But it's really best to use a roller to get the cat hair off before washing, especially if you use laundromat or apartment building washers, to be polite.