Honestly, there is a lot of myths when it comes to storing a car. Depending on how long you store it is what you should really do.
some things that were said in this thread:
Add fuel stabelizer - I would agree with this if you are planning on storing the car for more than 6 months. However, think about this: Car lots have hundreds of cars in their inventories, some of them dont move for months. The fuel that they put in them is the cheapest that they can get, and usually only put a max of 5 gallons in them. They are left out side for months on end, and never have a problem with the fuel system from sitting. Where the problem comes in is via condensation that gets built up in the gas tank. What I would recommend is either A, fill up the gas tank all the way up when you store it (fill it with premium) or drain as much of the gas out of the tank and then store the car. This will help eliminate the vaper. I tend to fill the car to the top, and then in 4 months when the car comes up, I dont have to go to the gas station.
Another thing that I have seen is to jack up the car so that you dont get flat spots. Once again, look at the car dealerships. We have some cars that havent moved from their spots for months on end, and none of them have flat spots. Now, back in the days of Bias Ply tires, you had to do that, however with the steel belted tires and the technology that they use in them, you shouldnt have them come out of round. The only time I would say do anything like jacking up the tires off the ground is if you have summer only/drag radial/track tires on the car, as the cold weather can actually hurt the rubber compound (kind of like the exact oppisite of Blizzaks). For this I would either A-remove all of the tires and put them in my house (where the temp will be regulated to where it would be out side in the summer) and cover the brakes so that the moisture wont cause "lot Rot", or b - put on a set of steelies that you dont care about on the car. Now if you put your vehicle in a Climate controlled unit, you wont have to worry about any of this.
Last, I would make sure that my coolant is up to par. This is simple maintiance that should be obvious,