I've done some work with Enrique and Fran who run the academy 'Elitennis' based at club de tenis Andres Gimeno. We ran an RPT course there last september and they are both awesome coaches, Fran especially has some great ideas for improving fitness both on and off court.
I tweet - @ashtennis guru (no spaces)
I Shoot - www.flickr.com/photos/ashtennis guru/ (again no spaces! grrr)