If you go to Google Maps Labs (click the beaker icon at Google Maps), you can enable aerial imagery, which covers Portland. It's a lot like Microsoft's aerial imagery, but more up to date.
Somehow I missed this before, but it's pretty cool. There are some fun things you can find, like a bunch of MAX trains in service and stuff. It's great for figuring out where exactly I'm going when it's a random Portland neighborhood I'm not familiar with.