This is a recent test done in houdini.It took me some time to study and research the ocean shader,since I have no ocean experience before.in this version,you can see the foam near the center is over stretched,this problem will be fixed up in the next version.
A small test I did 2008 with my maya implementation of the houdini ocean toolkit and my foam shader. The foam does not need any particles or fluids. The video only focuses the foam simulation, not the ocean shading etc.
See my blog entry for more details: schnellhammer.net/blog/2010/water-foam-generation-tests/