Putting a Car Into Storage
Excerpt from Moss Motors Technical bulletin

If you're covering the vehicle, use a car cover that will allow moisture to escape. Any plastic or other waterproof material will trap moisture on the paintwork. If you are storing the vehicle outside, be advised that no car covers exist that will replace a garage. Cars stored outside also become a haven for all kinds of creatures, most of whom will be lousy tenants. Make a list of the steps taken to ready the car for storage, and leave it in the car. Not a bad idea to include your notes for “bringing it back to life." That way, you won’t be searching high and low for the information when that time comes.

Tune Up — The purpose here is to stop the guessing games that come next time you try to start the car. If everything is in good working order when you stop driving the car, sorting out a problem next season will be easy because you know the basics were in good order.
Battery - Disconnect the battery, and remove it from the car. Use a battery maintenance device to keep the battery(s) fully charged. keeping the battery fully charged will prevent sulfation, which can render a battery useless in a matter of months.
Brakes — Release the handbrake and chock the wheels. Brake shoes can become firmly rusted to the drums in a matter of months.
Cooling System — The coolant should be no more than 30% to 50% antifreeze. If the coolant is over 1 year old, drain and refill the system using a name brand antifreeze designed for use in older cars.
Belts — Slacken the tension on the fan belt and any auxiliary belts.
Tires — If the car will be sitting for the winter, jack the car up and place jack stands under the rear axle and the front suspension.
Exhaust — Plug the tail pipe(s) with a rag or rubber ball and tape it in place. It will keep the mice from building a nest in the exhaust, or worse, in the engine.