L.C.
Fiona,
It's funny you mention "tennis academy" in your post. I grew up in Port Washington (on Long Island) where the very well known Tennis Academy is located (I actually went there for some lessons when I was young...not that you could tell now).
Alpharetta is a very active area with most neighborhoods (called subdivisions here) having their own tennis courts and teams.
Are you interested in the tennis for you or your kids (or both)? Depending on the subdivision, there are plenty of tennis teams you can join at many levels of abilities. To name just a few: womens, mens, mixed doubles, juniors (separated by age groups).
There are a number of organizations you can play on for teams: ALTA (Atlanta Lawn and Tennis Association), USTA, KSwiss (for singles matches), T2 (for doubles). I play on all but KSwiss. I really should play KSwiss to improve my game but it's difficult to fit it all in with my kids and job. Each league has many levels for the different abilities.
One of the first questions I was asked when I moved here was: "Do you play tennis?" and I won't be surprised if that is one of the first questions you'll be asked as well.
You'll love it down here! You can email me at ____@____.com if you have any questions.
Hope to meet you some day!
L.