I was just watching Colbert Report, an old one, that had a paleantologists(sp) on there, who had discovered a fossil from 375 million years ago, that was a link between fishes and the first land creatures. It had parts of a land creature in it, and still parts of a fish, and was believed to live in shallow water and ventured onto land occasionally.

It was called Tiktaalik, and here is a link to a transcript of a Nature documentary on its discovery.

: Nature

I think thats a pretty good example of evolution in action right there.