If you're storing the battery with the car, put it on a charger that's designed for long-term storage (provided you have access to power). Take a look at
http://www.batterytender.com for some choices. There are other, similar chargers out there. Batteries don't like to sit for that long without use and may not hold a charge afterwards.
I have recent, personal experience on this topic: My Mustang was stuck in the back of my garage for 8-10 months, blocked in by construction material for a home addition. I didn't get a chance to start it regularly, and only put it on a charger occasionally (I don't yet have a Battery Tender). When I finally got the car going again, the battery wouldn't hold a charge (a DieHard, though with only 6 months left on the warranty). I'm certain the battery would have been usable if I had a Battery Tender.
The Battery Tender would have cost less than the battery I just bought - plus I still need a Battery Tender. That's what I get for being too cheap...
