H2Odog has some good ones in the free section

NASA Worldwind was around a long time before GE came out. However, unless they have significantly updated it, GE is the far more capable of the two.

I agree with all of the above - it's an excellent, easy to use package that gives very good results.

A good tutorial on wakes and foam here: http://www.paroge.com/vde/tutorial/default.htm I can also recommend "Sea Vue" by Monsoon - available over at 3dCommune.com, it has some very good effects in it. For a simple wake I sometimes use the text letter "V". Make it big, round the edges, apply a foam texture and position carefully. It will only work with a sea made from a terrain rather than a water plane, but with a bit of effort it can be quite effective.