Hey,

SMIME.org was created to promote email encryption usage, by providing
help and references to email encryption products and standards.
Although S/MIME standard is supported by most of the email clients, it
is not widely used. The supplied information in SMIME.org will help
all kind of users, from end-users to developers, to easily use and
integrate S/MIME.

http://www.smime.org

Chen Levkovich