Justbme, the disposable waterproof cameras at Wal-Mart take pretty darn good pictures. The dive shops also sell camera cases, but they're really expensive if you're not going to be using them all the time. The tubing should be relaxing, yet invigorating, the water can be...um...well, refreshing.
I, personally, like water shoes. I wear them instead of sneakers. I got mine on board, but they sell them in Wal-Mart and Dive Shops, too. Remember the sunscreen and have a ball!