rstdiff - Generate a diff from two reStructuredText input files
rstdiff.py [options]... old-reST [new-reST [diff-output]]
Generates a structural diff from two reStructuredText input documents and produces an annotated result.
Try
rstdiff.py --help
for an explanation of all options.
rstdiff is available from
http://www.merten-home.de/FreeSoftware/rstdiff/
and the Docutils sandbox