Not quite... Southwest is now booking travel through October 28. The booking window for Southwest varies. You usually can't book travel more than 6 months in advance, and I've never seen the booking window open any less than 90 days from a date.
One advantage of this is that Southwest very rarely changes its flight schedules once they are published.
In regard to the original post, I wouldn't expect March 2006 to open for booking before September, and more likely it won't open until October. March can be a busy travel month since spring breaks can fall then, I'd keep a close watch on when Southwest's dates open up for you and jump on a good fare once you see it... it won't be around long!
Thanks everyone! I really hate this 'airfare' game of catching a good fare at just the right time, BUT I hate driving 17 hours to Florida too! So I will cross my fingers and hope we can get something at a good price.
DJ