Try MapQuest . Finally, if you haven't already done so, please read the Vinyl Tourist's Caveat . The vinyl section is very well organized and there is an amazing collection of 78's sorted by genre and style in boxes beneath the LP bins. Generally fair prices and they are happy to let you preview sealed CD's. This shop takes it's name from its original incarnation on a former school bus, but is now permanently installed on a side street near Jackson Square.
Prices are on the high side of fair, but still worth a look.
12-inch dance singles are the flavor of choice and here I was able to find a couple of imported sides by Leftfield. Now we venture into the real N'Awlins. Jim Russell's shop is a ground-floor warehouse somewhat removed from the French Quarter. Negotiation may be possible. Another antiquarian book store in the French Quarter, this shop has a minuscule pile of overpriced jazz LP's way in the back corner.