Many visitors choose to plot a course through the Metro system instead of driving. This is a system of buses and trains that run throughout the Washington, DC metropolitan area, and is probably the quickest way to get around town. The train system runs both above and underground, and has five color-coded routes (red, orange, yellow, green, and blue) to make navigation easy. There are literally hundreds of buses and convenient routes that include connections to the train and park-and-ride stations and shuttles to and from the airport. On the Washington Metropolitan Area Transit Authority's Web site, you can find metro maps, schedules, fares, and more.
Here's some other helpful links to the Washington DC area: