Here is a list of additional information sources about sendmail.
http://www.sendmail.org - Home page for sendmail
http://www.sendmail.org/faq - FAQ for sendmail
http://www.sendmail.org/m4/readme.html - README for new sendmail configuration files
http://www.sendmail.org/sun-specific/migration+sun.html - Differences between sendmail delivered with the 2.6 release and release 7.