-caveat: I'm biased. I do a booth here, usually, and in my opinion, this is the single BEST event during which to visit New Orleans, including Mardi Gras. So start making your plans to attend! The music is without comparision (the best), like the food (the best), and the people (the friendliest). Here's the official website where you can see whose playing:
New Orleans Jazz & Heritage Festival | April 25 - May 4, 2008
and check out the details... I have a call in to my bandmate Rockstar Rob Savoy, who works for the fest, about any tips regarding Airstream parking, but in a basic websearch I found this site that has fairly up-to-date reviews of local parking spots:
RVparkreviews.com :: New Orleans, Louisiana
..and I would guess that if you arrived early enough and were boondock-able you could just park in a local secure parking lot for around $20 per day and go for it. If I had more room I'd offer some free parking but I'm afraid we only have 6" to spare out behind the Safari. Oh wait, I just had a brainstorm regarding my neighborhood parking lot...I will have to go talk to these guys and see if we can cut a deal...
..I will be posting any updates I can gather. Bottom line is: if you're curious about visiting New Orleans (and YES, we need you!) this is THE event to come for...