Hey Sand-man J,
As I'm sure you are no doubt aware, there are about a gazillion hot springs in your general area, since the Cascades are a volcanic mountain range, after all. I personally don't know of any specific ones off hand, but I met this guy named Skip a few years ago at a Verde Valley Hot Springs in Arizona that publishes a quarterly subscription newletter, The Hot Springs Gazette. He was a really cool guy that goes around to various hot springs all over the world, takes a picture, writes a description, measures the water temp, drinks a beer, and then publishes his evaluations in the gazette. Here's the link to his web site.
http://www.hotspringsgazette.com/
Follow the "Hot Springs Links" on his home page, you may find some near you. Otherwise, I know for a fact that there are several good guide books, the names of which (of course) I don't have a clue about.
IMHO, there's not much better than soaking in a hot spring in the mountains. Have fun!
...but it seemed like such a good idea at the time...