Glad you enjoyed 'Treme'. One of the questions we locals have is how well it's been accepted outside of New Orleans.
A primer on the local music scene, eh? Wow, where do you begin - the scene here is so rich and vibrant, with very deep roots.
For a starter, set your browser to 
WWOZ-FM. They have a live internet stream and a lot of the DJs post their playlists online. Programs you might be interested in are:
 - Trad Jazz - weekdaze 9 - 11 am
 - New Orleans Music Show - weekdaze 11 am - 2 pm  (nothin' but local artist, all genres)
 - Contemporary Jazz - weekdaze 4 - 7 pm; Emphasis on 'Comtemporary', but not necessarily local artitsts. 
Good luck.