Make sure to match when you dryhop to when the brew's flavor will peak. Don't dryhop after 2-3 weeks, drop in a keg and start drinking, you'll do a disservice to the beer. I as well as others find that the brew typically will get better and better. If you think it is best at 3 months, then you may want to age that in the keg for 2 months then dryhop for a week, carb and drink. That way both the brew and the hop aroma are at their best at the same time.If you are going to spend the money for the aroma, then you want the aroma vibrant! Drink it faster so that the aroma doesn't go away. The beer will still be beer, but without the beautiful smell of hops.
This was a very good podcast about dry-hopping.
The Brewing Network.com - Shows and Podcasts: Brew Strong
Um... I agree