Welcome (eventually) to Seattle.
The Cascade Cycling club has a lot of cycling resources in the area - message boards, links to local governments that have route maps, and a full list of area bike shops:
www.cascade.org.
I'm afraid that - ever since the invention of the derailleur - I've been a fan of gears so I can't help you on the fixie / SS front. My impression is that a store called Velo Shop on Capitol Hill is fixie friendly.