If you don't mind driving south to Sarasota on Saturday mornings, the Art Center Sarasota has life sessions with live models Saturdays 9:30 am to 12:30 pm
Guests are welcome; fee is $10 (Members $8). Check out their website at artsarasota.org.
We're such a small town, I'm thinking Tampa/St. Pete/Clearwater must offer more. Check art programs at the local universities, most have continuing education offerings/live model sessions, especially in the summer. I highly recommend making the jump and taking advantage of these options; don't think that you're going to be the only beginner, either--that is never the case.
