My intention is to thru-hike the PCT in 2008, and I'll start with a tarptent, but I too am thinking of switching to a hammock along the way.
My tentative plan is that my wife will meet me near Ashland, basically at the CA/OR border. We'll hike together just to Crater Lake and I'll use the hammock in that stretch, see how I feel at that point after all of California in a tent. My hammock setup is a little heavier, but I really like the flexibility of walking as late as I want to and then just finding two trees, i.e., the ability to walk later into the day, particularly later in the trip as the days start getting shorter (reduced hours of daylight). But of course, those start to get to be colder days too. I have a ~10-day solo trip planned for next month (September) in WA state with the hammock to get a better sense for whether I'll have any temperature issues, and how much clothing to bring --- I expect it will work fine.
Sounds like we will be there about the same time. I'll either be hangin in the Olympics ( probably Hoh River trail ) or the North Cascades 9/1- 9/8. I'm also trying to figure how it will work with , most likely, a required bear proof food canister. Extra weight and volume, and I wonder how many we will need for a weeks worth of food for 4 people?