Found an interesting new book on Amazon - Acrylic Revolution by Nancy Reyner. It's not available here till the end of June but should be available in the USA now. Have put it on my wish list. Had a look at the author's website and was impressed by her paintings.
http://www.amazon.co.uk/Acrylic-Revolution-Techniques-Working-Versatile/dp/1581808046/ref=pd_bbs_sr_1/026-2117146-9726027?ie=UTF8&s=books&qid=1175357794&sr=8-1