here are some resources for this important component of your farm. from a Washington State agronomist.

Cover Crop Chart - Remember it's 48 pages - before you press the print key....
http://www.ars.usda.gov/Services/docs.htm?docid=20323
Youtube Webinar
http://www.youtube.com/user/NCATATTRA#p/u/2/zjI2zWf4uMI