Autosports Northwest  - Spokane Autocross club

North West Region SCCA - Seattle Autocross club (Packwood/Bremerton)

Western Washington Sports Car Council - clubs that operate under the WWSCC umbrella

Oregon Region SCCA - Portland Autocross club (Packwood/PIR)

Big Sky (Montana) SCCA

For the hill-climbers: Northwest Hillclimb Assc.

Pacific NorthWest Mustang Club

Here's a couple for people trying to determine SCCA Classes for their car:
Comparison of permitted mods in SCCA classes
SCCA Class descriptions