These are the steps that I took to winterize my car (99 RT/10) last winter, which was the first winter I had the car. I do not have a heated garage, so keep that in mind.
1. I went to home depot and got a large pastic tarp to put on the floor.
2. Bought a float mode battery charger that works great. Here is a link of the one I bought:
http://store.schumachermart.com/sem-1562a.html Worked very well!
3. I would not alarm the car, because alarming the car seemed to drain my battery down very quickly and after coming out of storage last year I had to get a new battery. So my advice would be not to alarm it.
4. Before putting it away I got the oil changed and put a good coat of wax on it, when coming out of winter storage I did not change the oil again.
5. Covered the car with my dodge viper car cover (has the viper logo embroidered on the front...not sure if this is something you can buy or if it just came with the car).
6. Made sure the windows were cracked a bit.
7. Inflatted the tires close to max PSI to help prevent flat spotting.
8. Moved the car forward and back every few weeks to ensure no flat spotting occured on the rubber.
9. If mice might be an issue, put traps near the car. I have also heard putting dryer sheets in the engine bay helps deter the little rodents.
Here is a good site that provides some insights....it seems to be more geared to older style autos, but still a good reference.
http://www.dccarcare.com/tipowk/tipowk15.html