A few months ago Google Maps added bicycling directions as one of the options for how to get from A to B on their maps. There's a warning that "bicycling directions are in beta", and some of the early routes I tried were very silly, like going 4 blocks out of the way to end up going the wrong direction on the Hawthorne Bridge sidewalk. There is a link you can click on every map to report problems, and they have been dutifully swatting them down as people send them in -- for example, the Hawthorne Bridge issues got taken care of pretty quickly. I'm sure that eventually the Google biking directions will be an incredibly useful tool, but they're not ready for prime time yet.
If you're planning some Portland bicycle pub crawls this summer, your best resource is Metro's Bike There map, because some of the Google directions are more dangerous than they have to be, and others are just physically impossible. Another option which is better than Google right now is byCycle.org, though it too is labeled "beta", and hasn't been updated for three years.
One route Google can't seem to get right is one of my favorite bugaboos -- biking to Hopworks Urban Brewery. Powell Boulevard is never a fun place to bike, even for hardened urban riders, so a year and a half ago I made a custom Google map describing some of the best approaches to Hopworks. Because there's no road to the pub from south of Powell, at some point you have to be eastbound on Powell, or possibly westbound on the south sidewalk (and if you're doing that, I hope you're walking your bike). If you're approaching from the north and want the least amount of hassle with Powell, the crosswalk at 28th Place pictured here is your best bet -- sneak up to it through the McDonald's parking lot.
Now consider the Google biking directions to HUB, which currently insist on a right turn on Powell at 31st -- even if you start out northwest of Hopworks -- with the final instruction being "Destination will be on the left". That might be reasonable, if the directions had you take the crosswalk at 31st, and walk your bike against traffic on the far sidewalk. But if you weren't familiar with the area, you might think you could take a right and then merge over to the turn lane and wait for an opening to make your left. It's theoretically possible, but you'll sure need a beer after you pull it off. Take my advice, use the It's Pub Night map to Hopworks instead.
Even no-brainers like the route from the Horse Brass to the Lucky Lab are not very good yet. Most people would stay on Taylor when Google sends you to Salmon at 41st, since the pedestrian stoplight gives you more chances to cross Cesar Chavez (39th) than you'd get on Salmon, and then there are no stop signs on Taylor until it dead-ends at 35th. Later on, Google meanders you off of Salmon when it's at its bicycling best, between 20th and 12th. Those are just little annoyances, but if you reverse the directions and go from the Lucky Lab to the Horse Brass, Google sends you right up Hawthorne to 41st. You might do that very late at night, but even then, Salmon/Taylor is the nicer route.
Interestingly, even though byCycle.org has been dormant for years -- and is far from perfect -- it passes the tests above better than Google does today. It chooses the correct routes both ways between the Brass and the Lab, at Hopworks it gives you a right turn off of Powell instead of a left, and it keeps you on the east side of the river if you're headed to Upright. Its Upright directions are not great -- even with its "safer" setting it puts you on SE 12th for a mile or so -- though if you're headed south from Upright, it correctly finds the bike path along the Eastbank Esplanade.
The Google biking directions are getting better all the time, and will someday be very valuable. But don't count on them this year. As I mentioned above, what you really want is the Bike There map. There's a new edition out this year, and it will never put you in the suicide lane on Powell Boulevard or make you fly up to a bridge from the road underneath it.