It’s easy to find happy hours in Portland, with several local sites dedicated to the subject. In particular Bar Fly and Unthirsty.
My favorite is UrbanDrinks.com.
The happy hour time charts (downtown‘s for example) make it easy to map out your drinking travels throughout the day.
But my favorite feature is the user submitted pub crawls. I even created one myself: Milwaukee Ave: Powell to Bybee.
Still waiting on a date for the crawl…