There are really a lot of things u can do there and there are so many travel agents there, u just simply walk in any of them and choose the program u like.
To name a few:
1: Diving, must try, a lot of fun. There are lot of choices for the diving place, Racha is the one we go, good for beginners.
2: Go other small islands near Phuket. PP is a good choice, advise you to stay there for 1 night. one day program is too rush for PP. Better to rent a long tail boat to travel around PP island, snorkling and experience the sunset on the sea. Very beautiful.
3: Massage: Massage is cheap there, 2 hours oil massage is only around 700Bhat... A famous massage place to recommand is : Let's relax... really very relax. must try, but a little bit more expensive than other places.