They are in the Faubourg Marigny, which didn't really flood. Michael's Bicycles on Frenchmen also was not damaged and has been open for some time. Bayou Bicycles, for those of you familiar with the city, took heavy water and has not reopened.
Groups across the country sent bikes to Plan B after the storm, and now they have a lot.
Another post-Katrina phenomenon is that people gutting their houses are throwing out perfectly good bikes, sometimes bikes that didn't even flood. A friend of mine pulled a very nice Raleigh Sports three-speed out of the trash, and I found an old triathlon bike (took the wheels and brakes) and an old Huffy (which I cleaned up and gave to a bikeless friend). I have turned away dozens of department store bikes.