This method to do water is very mathematical but gives therefore a very realistic look. Specially the foam on the waves are great. The splash on the image appears if two waves hit each other.

Link to the article:
http://www.gamasutra.com/gdce/2001/jensen/jensen_01.htm

and this is the paper:

http://whitenight-games.chez-alice.fr/Docs/Water.pdf

A method in which a grid is projected in post-perspective camera space. This gives an even-spaced grid so the detail level of the water is the same over the whole screen. The image below shows the implementation of it in the 3D engine jME.

Link to the paper:
http://graphics.cs.lth.se/theses/projects/projgrid/

A method to create realistic water by combining normal mapping and vertex displacement. The water looks best when viewed from a distance.

Link to the chapter in GPU Gems that describes this method:
http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter18.html

This technique seams to be very nice when doing rendering of shallow water in close ups. It’s presented as the following in the abstract:

“ We present a real-time technique to render realistic water volumes. Water volumes are represented as the space enclosed between a ground heightfield and an animable water surface heightfield. This representation allows the application of recent GPU-based heightfield rendering algorithms. Our method is a simplified raytracing approach which correctly handles reflections and refractions and allows us to render complex effects such as light absorption, refracted shadows and refracted caustics. It runs at high framerates by exploiting the power of the latest graphic cards, and could be used in real-time applications like video games, or interactive simulation. “

And looks like this:

Source for the paper:
http://artis.imag.fr/Publications/2006/BD06a/