Well, you could start out by going for walks! No, really. I live in Fla. too, so I either walk early in the day or I go to an indoor mall and walk there.
You could also look into exercise videos like "Walk Away The Pounds" or many, many others that will give you a workout at home. Some can be found at libraries. If you have cable or satellite TV there are also channels that have workouts.
I joined the YMCA when I first started losing, and I would go there 5 or 6 times a week, doing different things each day and resting every 3 days. I still belong to a gym--a great thing in the summers.
The important thing is, if you aren't used to exercise, start off with something manageable, that you can fit in. Don't think you have to go from zero to marathons in a short time! Keep it simple...