Wat Tha Rua is a Wat set back from the main road (Thepkasattri Road - 402) and can easily be missed. There is also a Chinese Shrine called Tha Rua shrine if you visit here - both are worth visiting.
The beauty of this pace is the feeling of serenity you receive when you first arrive. There is a feeling of calm that you get as soon as you walk past the first Buddha figurine (above).
At the time of writing (May 2012) the main temple is undergoing some maintenance work which you may feel is a reason to wait but it should not. There was a private ceremony ongoing whilst we were there but this only added to our pleasure. The Thai people only welcomed us in to share celebrating Buddhism.
There are any number of sources of information to indicate how you are supposed to act when you walk into a Wat. Please remember to be respectful when you visit places of religious significance.
I would visit here simple because of the feeling of peace that I had when I entered - it was interesting to note that when I looked on Google maps I found that the entrance was covered and not obvious.
Here is a Google Map of the Wats in Phuket which I have personally visited.
View Buddhist Temples in Phuket in a larger map