It all depends what you are looking to do. I'd start here:
http://www.sendmail.org/doc/
Red Hat's site has good documentation (albeit somewhat old) on how to setup and configure sendmail.
Also, check your local library's web site. If you already have an account, some libraries let you checkout E-books for a limited time. Depending upon the library all you should need is your library card # and the password you originally setup for their web access.
Thnx in advance
