I have mine mounted at the nose of my board. I use the GoPro surf mount. Like Erin said, you could use any mounts such as surf mount, flat adhesive mount, or even a suction cup to your board. Its all about personal preference I guess. In addition, it all depends on what perspective you want. Self POV, head angle, chest angle, etc... Correct me if I'm wrong anyone...
Most people have mounted it toward the front nose of the board. Many have personally made their mounts with suction cups, etc. The camera is typically pointing toward them while on the board but you can move it any direction you like. Hope that helps a little.