http://www.atlantafalcons.com/team/article.jsp?id=18356 http://www.boston.com/sports/football/patriots/reiss_pieces/2007/03/pats_moves_8.html
Hartwell was a very good 3-4 ILB with the Ravens. Now to be fair he's suffered a pretty serious injury (achillies) since then, but at the right cost he'd be a very interesting addition.
Hartwell played next to Lewis in the 3-4 and was a better player in the system then Lewis was, only he isn't flashy, so he didn't get publisized like Lewis does.