Even in the southern USA there are distinctions between vinegar based barbecue (North Carolina style), tomato based barbecue (Eastern Tenessee) and dry rub (Memphis). I have had barbecue in North Carolina (at the legendary Bullock's in Durham, NC) and it is a vinegar based BBQ prepared differently than the tomato based sauces, but as delicious. In NC all BBQ is served with hush puppies, which are onion flavored cornmeal balls deep fried or boiled. I have also had barbecue in Kansas City which is more in line with what is described by Alfie, who should note that is just one style and there are many different styles throughout the southern and midwestern USA.
There is now a southern-style barbecue chain restaurant called Brother Jimmy's which has made its way into New York City which differentiates between North Carolina and South Carolina styles. I believe that the South Carolina style and the eastern Tennessee style are similar in using tomato based BBQ sauce.
http://www.brotherjimmys.com/