The LA Times has a really interesting article about Area 51. With the declassification of the top secret OXCART project, five ex-Area 51 employees can now spill their guts about their experiences there, including speculation about where many UFO stories have originated from. Cool stuff.
All you UFOlogists, aircraft fan-atics and AREA 51 historians probably are already all over this story. The folks at IO9 seem to think that these newly recounted stories may themselves be part of the government's UFO conspiracy.
From Wikipedia, I see OXCART was the code name for the Lockheed A-12, a precursor to the SR-71 Blackbird (shown above).