Washington State University has been involved in renewable energy projects for a long time. You might find some good advice there on local conditions and resources: http://www.energy.wsu.edu/documents/renewa...dersOct2009.pdf
, and someone you can speak to as a consultant on staff.
You might also want to look for a local chapter of the USGBC (US Green Building Council), and visit solarwashington.org
Solar Washington posts a list of ongoing workshops and meetings. There is one listed for May 1 in Olympia titled something like "Five things you should know about adding Solar to your Home."
Are you planning to grid-tie your system?
I've noticed a lot more folks selling systems both locally and on the web, and exhibiting at the home shows. I feel that's both a good and bad thing: more competition usually means the prices drop some, but there are more chances for fly-by-nights, as well.
The federal tax credits don't expire until 2016, so I'd take my time to find someone relatively local, knowledgeable, and experienced as an installer. It's a big investment for a 5kw system, even after the tax credits, and there are a lot of options out there.
I'm particularly interested in the solar products integrated into roofing, and the new cylindrical pvs we saw at the Solar Decathlon in D.C. last year, which are rated for winds in excess of 100 mph, a factor for us here in the hurricane zones....