does anyone know of any aftermarket email encryption programs that can be installed on the newer 7000+ series blackberrys? where to find them?
preferably ones that dont have a monthly subscription cost..

There is no need to purchase encryption software for Blackberries!
They have a solution embeded in the device call Triple DES Encryption that fully encrypts and decrypts all personal information that is being transmitted and received.

Which is true if and only if you have a BES. Then all e-mail between the BlackBerry and your host e-mail server is encrypted. And I believe BES 4 also include AES, a stronger encryption. This does not apply for BWC/BIS e-mail.