Spamass-milter or spamass-milt (http://savannah.nongnu.org/projects/spamass-milt/) seems to be the de-facto standard for using SpamAssassin as a milter for Sendmail or Postfix, but it is woefully under-maintained. (The security problem mentioned on https://wiki.apache.org/spamassassin/IntegratedInMta has been fixed, though.) I recently sent an email to the two previous maintainers and to the mailing list inquiring about the status of the project, and got no response.
It seems like something should be done about this situation. I am considering putting a fork of the project on GitHub, and trying to maintain it there. Is anyone else here interested in seeing that happen? Or do you have other ideas about what should be done? Andy