There could be other sources of play, so don't go out buying new bearings until you've taken them out, cleaned them in a solvent (gasoline or mineral spirits) and looked at them. With regular (every 60K or so, or maybe every time you do your brake pads) cleaning and lubing, wheel bearings could conceivably last the life of your car, so don't change them just for good measure. If they are not pitted or grooved and you don't hear a gravel-like rumble when you spin the wheel, you probably just need to grease them, reinstall and adjust the torque.

The inner bearing is not difficult. You will need a punch or a drift to get the races out. In a pinch you could use the round end of a long socket extension, but take some care putting the new races in.