<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by j379pa:
The other option is the DC area transit system (sorry I can't give a specific name, but you should be able to find it on-lineJP</font>
You're thinking of the MARC trains which run Mon-Fri from BWI station into Union Station. Last I used them they were $5 one way and $8, but the fares may have gone up by now.
http://www.mtamaryland.com/schedules...c_schedule.cfm