Favor alert! I was strolling through Powell's Books the other day and came across these cute little all-weather notebooks from Rite In The Rain.
Can't think of very many things that would be more Northwest-y to give to your guests than this! A waterproof notebook in which they can record their thoughts about the weekend, the wine tastings they might go to during their visit, or important names and numbers as they catch up with friends and family.
The great thing is, the fiber is from FSC Certified sources, printed with soy ink, the covers are made of post-consumer content, and the whole shebang is made in USA in the Pacific Northwest. You can even order custom imprints and sizes.
If you have tech-savvy guests, have them make use of the Portland "Twisitor's Center" by following @travelportland on twitter.com . Your guests can then post questions with the tag #inpdx and receive real-time advice on where to eat, shop, and play during their wedding-weekend downtime. Thanks to VentureBeat for the tip!