Trimble Outdoors and MapMyRide - large number of area maps by local cyclists. Trimble maps are free to print. MapMyRide assesses a printing charge.
Google Bicycle Maps - new Google Maps feature adding Bicycle to the drop-down box to select mode of travel.
Bikely.com - user-driven mapping site where cyclists can find a route someone else has already ridden.
Get Fit - Have Fun - Cycle Tri-Cities
Richland Bike Trail and Path Map
Snoqualmie Pass Bike Construction Detour
Cycling Tri-Cities Map (PDF version of regional map by BF Council of Governments. Scroll down page to see map links.)
Maplets Bike Map App for iPad/iPhone. Tri-City, Walla Walla, Seattle, many more cycling maps available for download.
Windows Phone 7 maps - Seattle, King County, and others.