How do you add refrigerant to your air conditioner?

Most automotive places have a freon recharge kits. http://www.bargainoutfitters.com/cb/cb.asp?a=230769&kwtid=203671 I prefer the one with the gauge on it and remember to attach it to the low pressure side. If you are doing a full take down and refill you will need some guages, a vacuum pump, and a recharge system. Because leting the freon out into the air is against the law.