Do tours in New Orleans require advance registration?

There are a million competing tours. Talk to your hotel once you get there and they will find something appropriate.

No, they don't. Your hotel will be able to set you up, or you can collect information and call yourself.

We set up one tour ahead of time just because we wanted to make sure we were able to take it - it was a swamp tour with Capt Nick. This tour was more expensive than many tours, but it was worth it. Basically, get get a private guide and go out in a small boat. Other than that, we just made reservations when we got there. For a plantation tour we just talk to the people at our hotel and they set it up. For a walking tour we just showed up at the appointed time and place and paid our money.

If your interested in smaller tours it sometimes takes a day or two for them to get enough people to fill the tour. We called one day and went the next.

Alot of the tour places offer discounts for advance reservations, which could even be made the same day as your tour. As long as it's not like 5 minutes before, I think you'll be OK. Another hint is to shop around the Visitor Info Centers around town -- they will compete for your business and you might get a better discount there.