Walking animation with a dress

I'm working on a project that will have a woman in a dress, and I'm wondering what's the best practice for incorporating that into the walk animation.  Should we set it up with her legs (under the dress) rigged for the walk, and the dress as a separate layer over top?  Is there a good way to make the dress move as she walks to mimic her legs underneath?  Any examples would be greatly appreciated.

Thanks