[Reincarnate]

NASA isn't working on this in any serious capacity -- it's more of a "Hey here's a cool 3D rendering of such a ship and I'll run some tests with lasers" thing.

Straight from NASA:
http://www.nasa.gov/centers/glenn/te...rpstat_prt.htm
http://www.nasa.gov/centers/glenn/te...p/socanwe.html

I'm no expert, but I'm not optimistic about FTL travel -- and I say that fully understanding that technological naysayers tend to be shown up in the end. Relativity pretty much shits all over it and forces you to invoke things like "negative energy density / negative mass" and "exotic matter." It's like saying "This awesomely cool technology would be possible as long as the matter that powers this technology actually exists."

Every once and a while this topic gets rehashed and it's usually just another repackaging of the Alcubierre drive.