I like fishing in South Louisiana and do it regularly. Depending on what you want to do there are many options.
I have fished mostly with Kirby LaCour. He is very good and is also a FFF fly casting instructor. He mostly fishes out of the west bank south of New Orleans. His prices are the best in the area. I fished about 20 days with him last year. http://www.redchasercharters.com/index.html
Mark Brockhoeft fishes a few miles north of where Kirby fishes. I have been with him a couple of times and find him pleasant and has good fishing. I don't think you are as likely to catch big fish with him. His trips are not very long runs and in smaller waters. http://www.bigredguides.com/index.html
I have a trip scheduled with Chas Marsh. I have never gone with him and only know him from reputation and talking with him for a few hours at a fly fishing conclave. He is very pleasant--in the summer he guides in Wyoming. 307.690.5305
Rick Waldner has a good reputation and ties probably the best spoon fly around. He is willing to stay on the water all day. 504.319.2256
With any of these guides, schedule ASAP. These are some of the most popular times to go.
All of the above can be fished while staying in Belle Chase (Riverside Hotel 504.391.0133) or NOLA. I personally like staying at the Woodland Plantation. It is an antebellum plantation that has excellent food, bar and pretty nice accommodations. The label of Southern Comfort is taken from a drawing of the plantation. http://www.woodlandplantation.com/
Gary Taylor fishes the east bank. I fished a couple of days with him last year and hit a bad stretch of weather and conditions--I did not do well and don't think it was his fault. I would have no problems scheduling a trip with him again. He fishes out of Slidell, LA (to the east of NOLA). 985.641.8532
There are more guides in the area. Some are good and some are bad. If you come up with a name, please feel free to PM me.
I forgot to mention that March could be windy.
Richard