Encrypted emails

["Jair" <jairgerald () hotmail com>]

Hi There,

I have a CA in my windows 2000 active directory domain and my users are able
to send encrypted emails just to internal users in the organization( users
in the same active directory domain).
Are you aware of any way to send encrypted messages to users in a different
organization ( another email domain) ?

Thanks a lot in advance for your answer.