Most probably a California Ground Squirrel (Spermophilus beecheyi) although this one was found roadside on the Dalles Mountain in Klickitat County, Washington, March 9, 2012. The genus has been recently reclassified to Otospermophilus so you may find references under either name.
This little fellow looks like he would appreciate some fresh salad greens. A group of these critters are referred to as a “scurry”… which adequately describes their activity.
byLarry