7 Megapixel, can fit in the pocket <$500
"With the optional Cyber-shot Marine Pack (MPK-PHB), the Cyber-shot P150 can become an underwater camera with water resistance to a depth of up to 132 feet, with the option of using telephoto lenses."
I wonder how bulky that housing is - I'm sure it would preclude you from really surfing with it, even though the camera itself looks pretty small. 7 megapixels with a telephoto, though, you could just sit in the channel and get those close up barrel shots of you buddy...

http://www.extremetech.com/article2/0,1 ... 716,00.asp