Welcome aboard!!! +1 to all the advice that you've already been given.
Autocross season is getting ready to startup pretty soon and a few of the clubs will be having autocross schools. Here's the link for the one BMW is having in March
http://www.dfwmiata.com/threads/2187...March-3rd-2012. For a novice I'd highly recommend going to one if it works out. you'll get good instruction, lots of seat time and it's very inexpensive.
Just out of curiousity what part of the metromess are you located in?
Keith