Seattle Audobon Society
It's a great resource for events and classes etc.
http://www.seattleaudubon.org/birdweb/index.aspx
Also, the store in Burien (West Seattle), Wild Birds Unlimited, has a little club, and they schedule outings together (I think every weekend) but you could give them a call.
I live right on a river, three stories up, with lots of sky and foliage, 20 miles South of town. I've been in this spot since last April, and I have to say, we have plenty of life and variety here... with a marvelous, seasonal rotation. You never know what you'll see in the morning.
Even in the dead of Winter, I have Juvenile Bald Eagles, Cormorants, Hummingbirds, Goldeneyes, Canadians, Mergansers, Widgeons, Osprey, Red Tailed Hawks, Stellar jays, and sundry little fellows... Sparrows, Finches, Varied Thrushes, Robins, Chickadees.... ALL, just in the last few days.
I think it's a marvelous place to visit. I do envy you going to San Francisco though. I grew up there, and I've heard they've done some wonderful things to make a walking tour more enjoyable.
Best of luck