If the circuit breaker box is in the garage, and the walls are unfinished, It would be easy to add new breakers and run 14 ga romex (15 amp circuit) thru the studs to various locations on the walls of the garage.
However, if the breaker box is located elsewhere, and/or the walls are finished, you will have to have an electrician install a new breaker box in your garage. Then you can run shielded cable to recepticles mounted on the wall. You can also use shielded cable on the ceiling to connect to your light fixtures. Check your local codes first.
If at all possible, it's great to have a breaker box in the garage. Once it's there, you can do most of the work yourself, and this will also give you the possibility to add 240V recepticles in the future.
In my "Workshop in the Woods", on the ceiling, I have placed nine 4 ft T-8 fixtures and six incandescent fixtures. Having good light really makes a big difference.