Seems like at every major DC area meet there is a mall tour and a Air and Space Annex tour. So here is the Air and Space Annex Tour (not that I am providing tour guide services, this is my first time going there as well).
or meet at the annex at around 10:30 depending on traffic. (let us know so we look for you at the entrance. Cost: Admission is free. you pay $12 per car for parking, also costs if you want to see an imax show.
Right now its jsmeeker and myself. Post here if you are coming.
<edit> - I know this is a last minute thread so I'll try to not be disappointed if this is a zero reply thread.