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.