Frank,
A reference page would be awesome. It would take a while however something like the build stickies for camping could really be a benifit.
The one book that I am currently using is "Ray's Guides: Free Campgrounds in Washington State." It's a good little book however I have found a few discrepancies. I have tried a few others but this one has been the best to me so far.
Websites, I have a few. The one that I use the most is the National Forest Recreation site. For the clicky go to:
http://www.fs.fed.us/r6/wenatchee/ The feds have good stuff for me.
I have also been collecting maps. I have stumbled across a few sites like Trout Lake (North of Colville) that have been gems.
It all depends on what you are looking for in camping. I look for areas that are wilderness (hopefully fishing), with a toliet and safe enough to take a two year old. I don't need showers, golf courses or internet when I camp however some people do want those when they camp.
Camping sites do change over time. Some get popular while others have people strangely absent. I have seen some sites become decomission and new sites developed. Your best resourse is ask someone who is in the area regularly to see if anything has changed. It used to be ask a ranger however nowdays they are hard to come by.
Let me know if I can be of assistance.
Matt