Here's an old thread about wakeboarding near Annapolis
Forget about dcwake.com, I think it's no longer there.
What town are you in? I've ridden on the eastern shore before on the Chester river near Chestertown......great spot! Might be a bit far for you though.
skihaus on route 50 was/is the nearest wakeboard shop so you may want to contact them to see where all the riders go.