Encryption and e-mail

Hey all,
I was surfing around and found a site that got me thinking.
http://www.lockdownsoftware.s5.com
I was reading about their BFW encryption, and it sounds promising. Is there any other software out around that does what BFW does? and what does it cost?
E-mail encryption is relatively new to me, but it is a concern none the less.
-Goober