Hi, I'm looking to put a water effect into my application. I've heard good things about fresnel, and it 'sounds' not too difficult, but I'm having trouble finding a tutorial online. Does such a thing exist? Most of the hits that come up are white papers or teasers from books.

fresnel is what you use to compute the ratio of reflection/transmission of light. When light hits a surface, how much goes through the surface and how much reflects? Normally none goes through opaque objects (in 3D graphics land, not in the real world), so you don't care about fresnel or transmission at all.

The actual computation of fresnel inovlves a bunch of silly math that isn't necessary at all to get a decent result.

I liked the NVidia SDK demo of Vertex Texture Fetch Water. It comes with a white paper and a demo, as well as a quick explanation of fresnel and how you can fake it easily.