Since bhatnasx is no longer in the area, I figure it is up to all of us to help keep this up-to-date. Here are three new links for the Taxi fares (all of which are currently broken up above).
DCA -
http://www.mwaa.com/reagan/1193.htm
IAD -
http://www.washfly.com/Taxi_rate.htm
BWI -
http://www.bwiairporttaxi.com/ratetable.htm
and a new one for the metrorail system map.
http://www.wmata.com/rail/maps/map.cfm