I would suggest going to the southern area of Okinawa island. This is the most historic area. A tour of Shurijo (sp) castle and the historic areas around it will give you a great insight into the history of Okinawa and some beautiful architecture.
My next choice would be the fishing villages along some of the gorgeous beaches. I was amazed that there were as many beaches on the islands as there were. Okinawa is not just one island but many. I actually can't remember the name of the main island but Shruijo castle is located on the main island of Okinawa Island, where most ships dock.