This Colorado non-profit corporation has excellent information on durable plants for xeriscapes. Their focus is on the Western Garden and the Central Rocky Mountain Region in particular.
They offer information and ideas to help you select appropriate plants for your xeriscape. You can download designs, locate demonstration gardens to visit, find information on specific plants and search for plants using a variety of criteria. You can download pdf copies of their annual brochures which feature the winning plants each year from 1997 forward.
Check it out at http://plantselect.org/