Give some clues to what you like and how long you planning to be there. Travelling alone or with family ? Holiday or business ? Phuket is wonderful place with wide range of things to see and do. Many web sites will give info. Try this one for a start.
http://www.phuket.net/
Give some clues and then I'll try to advise you.
Going @ the end of June for 2 weeks, 2 24 year old girls planning a relaxing break away from city life, want to find some good bars, some handy nightlife tips, stunning beaches and hidden treasures.