The only way that most buyers can purchase a foreclosed property around the Portland region is to buy it from a broker with access to the "mulitple listing service" that is local in relation to where the property is. In the tri-county area, that MLS would be the Regional Multiple Listing Service (RMLS). In Marion County and the central Willamette Valley, it would be the Willamette Valley Multiple Listing Service (WVMLS).
Buying a "short sale" is another way to get a good home at a super low price, sometimes even better than a foreclosure. However, short sales take longer to close, and present some extra risks that some buyers are not willing to take.
I have handled both foreclosures and short sales, and I do a lot of work with banks, helping them with their REO portfolios. I also am an Accredited Buyer Representative. If you have additional questions, feel free to post them here, or to contact me directly.
Best of Luck,