There are probably a couple leagues in the Tampa where you live, but how close to the city you're in will vary. I mean if you really wanted to play, you could drive the extra distance to go there or you may have to convince your parents to take you if you can't drive.
To find Tampa volleyball leagues or any place really, just look in the newspaper, watch for flyers at school or posted around the city or state. When looking for Tampa volleyball leagues, you can check out the Tampa Bay Club Sport which is a beach volleyball league or you can just check out your local parks, YMCA, and beaches.
If you can't find any Tampa volleyball leagues, and you don't want to try another sport or drive, you need to keep your skills up for the following school year. You could do some volleyball drills if you had the place for it and if you were a setter, you may want to try going to some volleyball setter camps on the off season. Just remember to keep practicing and you'll be good wherever you play!