You can use this resource to print out the kind of map you will need to navigate your way around Washington, DC. Once you arrive in the city there are fantastic free resources provided near most tourist attractions that will give you free maps.
Just remember that the city is set up into four main parts: Northwest, Northeast, Southwest, and Southeast. Most of the main attractions are in the Northwest area of the city. You should also be careful about going to the Southwest and Southeast areas at night, as they are notoriously dangerous. That said, there are parts close to the National Mall that are safe.
Subway Metro Map
Download and print a map of the Subway
Download Maps for your iPod
Maps for your iPod courtesy of DCMetro
Map of Internet Hotspots
Find free Internet in Washington, DC
Interactive Map of the City
Fully interactive map of Washington, DC