Frankly I think some of the Democrats are dying to start impeachment proceedings, but they are waiting for their constituents to demand it. That's what Jim Moran said (D-VA) in so many words according to someone in my CDIC who happened to hear him speak. He's not my Congress critter, unfortunately.
There are things you can do which I have done and recommend, especially if you have a liberal-leaning Dem as your Congresscritter.
Write to your Congresscritter and lay out the arguments for impeachment. You can go to
http://www.democrats.com and
http://www.afterdowningstreet.org for more info on this.
Start a CDIC (Congressional District Impeachment Committee) or join one in your CD - also go to
http://www.democrats.com.Stage a demonstration for impeachment or against the war at an intersection near your Congresscritter's house. We just had one up in Vienna, VA this weekend (near Tom Davis' house, and it was a rousing success).
And just be persistant. In fact I need to write Davis again and thank him for voting yes for no escalation and also about impeachment again.
Rinse. Repeat.