A question for any government employees [View All]

I'm currently researching jobs and most that I find are for the government or government contractors. One common theme seems to be a background security check. My question is, what does this background check consist of? I've never been convicted of any crime and I pay my taxes. However, I have written several letters to the editor about Shrub and have openly protested the war. Is this something that they would look for? I am in no way against the government (I'm a Democrat afterall) but I disagree with the current administration. Could this affect me? Also, how does one become part of a "no fly" list? Were the people on this list arrested at a protest or is it just derived from some other source (letters to the editor, internet postings, etc...)?

Also, does anyone know how I can figure out what GS level I am? I worked for Census 2000 as an enumerator, took a test, and got some kind of clearance but I don't remember what that was.