I got it done at Costco. I called ahead to ask and since I didn't get the tires at Costco, they can help only I removed the wheel from the car, because they couldn't pull the car into the service bay.

Haven't tried just pulling up to the service bay, but that might work too. They seems cool enough. Even gave me a free green air cap. Now people KNOW I have N2. LMAO.

Ridiculous waste of money and time! Drive your car and the tires will not last long enough to make any difference.

IT'S A CAR, enjoy it!

Further reading... Only advised for the most serious airheads on this forum.
http://www.straightdope.com/columns/read/2694/is-it-better-to-fill-your-tires-with-nitrogen-instead-of-air