DSL availability is a function of physical constraints, i.e. how far away you are from the phone company's equipment. FOIS (fiber optics) does not have distance restrictions. But Verizon will start with the highest density areas and work their way out. They can probably make more money wiring 2 blocks in DC than doing all of St. Mary's County.
Cable is really the answer. Cable is a franchise, i.e. government sanctioned monopoly. If cable is not available in your area, then the best people to pressure are the County Commissioners.
It is an election year and it is not too late to make it an election issue.
I believe the current company was just awarded a very long contract. There are probably terms in their contract that specify what they have to do to expand coverage. Either way, you can still put pressure on the politicians. Its almost hard to believe that in 2006 entire parts of the county do not have access to cable.
If you can't get DSL or cable, somdwireless offers HS wireless in a limited area. Other than that, there is satellite. We have links here:
http://somd.com/relocate/internet/index.php