We still don’t have online loading but WMATA has announced the addition of 42 more SmarTrip purchase & reload locations. They have a listing of all the locations on their website but continue not to map the locations.
Well, I grabbed the addresses and slapped them into an online tool that plotted the locations, so here you go: The list of WMATA partner locations where you can buy a SmarTrip card and add value to it, as of November 6th, 2009. You can check to see where your nearest location is visually. Perhaps in the future WMATA will commit to a map & finder tool.