We just got back and did this tour while we were at Epcot. OMG DO IT! It is amazing. We had about an hour of class room instruction on basic dolphin antomy and conservation type stuff. Then we got into websuits and booties (provided) in the locker rooms. Bring or wear your swim suit. They provider lockers for your stuff. Be sure and remove all jjewlery. I coudln't get my wedding ring off and they did provide water proof tape to go over my ring, but it was pretty uncomfortable.
We got to watch a dolphin training session and then got to get into the water with the dolphins. You sit/stand on a ledge that slopes down into the tank. The water wasn't that deep where we were, maybe up to my waist (I"m 5'2") at the deepest part. We got to pet the dolphin and then learn different hand signals that they use in training. We also got an individual picture with the dolphin and a t-shirt.
Touching and intereacting with the dolphin was an amazing experience. I highly recommend it. It was a highlight of our trip.