And you could check out ATC Flight Training Center at Potomac Airfield. I think they are the closest ones.
Great flight school, and professional staff. They have a program where you pay $400 a month for the airplane, fly as much as you want as long as you pay for the fuel and instructor! That's an incredible good value if you can fly fairly intensive...
They operate 3 Cessna 172 one of which is a 2001 model, with AP and dual GPS(G430)...
One drawback is that you will need a special clearence by TSA in order to fly in and out of Potomac, due to the ADIZ/FRZ established over downtown DC.
http://www.lrn2fly.com