Discovery Cove is part of Sea World and is located across the street from them. We have gone twice and have LOVED it. The limit admission to about 1,000 people per day, so it never feels crowded.
The dolphin swim is about 45 min of interaction time with a dolphin, two trainers and a small group (6-9) people. Lots of photo ops to purchase from Discovery Cove. It is amazing to be up next to these animals!
Aside from the dolphin swim, there is a lazy river, with a swim up free flight aviary where you can feed all types of birds. There is also a coral reef for snorkeling and a stingray tank. The stingrays have had their stingers removed, and you can feed them at certain times of the day.
Our last trip there was in 2003, at which point the admission included a lunch, which was good, and 7 consecutive days worth of admission to Sea World itself.
While Discovery Cove can be expensive, when you factor in the Sea World admission, it isn't bad. If we didn't have two little boys who are too young to participate, we would go there every trip.
Hope this helps.