i would like to swim with dolphins ..where is the best place to do it

You could look into going to Discovery Cove. They offer an 'all-inclusive day' where you not only swim with bottlenose dolphins, but you're also given an opportunity to interact with birds, fish, and rays as well. I believe the cost is somewhere in the $200 range, though it definitely sounds as though you'll be getting your money's worth! If I wasn't a broke college student I'd definitely try to do something like this at Discovery Cove.
You could also try dolphinworld.com. I don't know much about that one though. Go to google.com and type in 'swim with dolphins', and you'll get a bunch of sites opened up.