My buddy Tanker, over at Mostly Cajun, has a good tutorial on the difference between Cajun and Creole, which most people outside of Louisiana consider synonymous, but we denizens of the state know better. Louisiana was settled by two French-speaking groups of people. The French thaht settled the New Orleans area as colonisists, and the Acadiens which came from french Canada. He even provides a map.
The folks around New Orleans acclimatized into the culture we call Creole which takes its culinary roots from many places with a more European cooking style.that absorbed many cultures from the islands in the Caribbean. Their cooking style also took cognizance of the fact that as a metropolitan area, there were more restaurants, and people had time to stand near the stove for complex recipes.
Cajun cooking, on the other hand, was more po-folks style. Meals tended to be simple, belly-filling fare that could be cooked quickly, or could be left alone on the stove without much tending. A gumbo, for example, can be assembled very quickly and left to simmer on the stove for a long time with just a simple stir when the cook passes by, between other chores. Jambalaya, on the other hand, is a very quick recipe, taking just a tiny bit longer than it takes to cook a pot of rice.
My food roots tend toward Cajun cooking for two reasons. First, my maternal grandmother was born on Avery Island and was raised in New Iberia. Second, my first wife (and the mother of my children) had a lot of Cajun in her blood and her family tended toward the culture. I learned as much Cajun cooking from her Dad as I leaned from my grandmother. Don't misunderstand, I enjoy going to New Orleans once a year or so, and sampling their cooking. It's quite nice. But, it ain't Cajun.