I'm just looking for a simple smart tool too. I like SVN part of SynProject but documentation approach seems to be too sophisticated. Another candidate, much simpler: http://dephicodetodoc.sourceforge.net/
I tried both DelphiCodeToDoc amd Doc-O-Matic. Doc-O-Matic has more features and generates better output. Specially it supports XML comments, which is my favorite one.