Take a look at the wiki: Economics Page (scroll down to topic Measuring unemployment and employment). There's a section on America. Also, Colman's diary Comparing unemployment statistics is on America too.

I contributed some information in this comment. It contains links to further information and discussion of American unemployment.

On the "dropped out of the market" people, a die-hard warrior of the marketista tribe, Diana Furchtgott-Roth of the Hudson Institute², makes out that the rise in the number of these "disappearing jobless" shows the success of the American economy, since Americans are now prosperous enough for moms to stay home and bring up their kiddies (which is what they always wanted to do, huh), and for youngsters to stay longer in school.

¹I know where you were really, you were in there fighting the good fight!
²The link to Furchtgott-Roth's screed is now broken. The Hudson Institute never seemed very proud of this "rebuttal" to Katharine Bradbury's study (pdf). I had a job getting hold of it, and now they seem to have pulled it. I'll email a copy to anyone who really, really wants one.