e-mail policies

[pablo gietz <pablo.gietz () nuevobersa com ar>]

Dear gurus

We are defining policies for the use of corporate e-mail, I have doubts 
about privacy of messages sent by employees. Since the e-mail system is 
intended for business use, we need to prevent sensitive information 
disclosure. If we respect the privacy , how can discover infidelity 
employee?
What is your opinion or the standard in this cases? What is the 
companies approach?

Thanks a lot.

--
Pablo A. C. Gietz
Jefe de Seguridad Informática
Nuevo Banco de Entre Ríos S.A.
Te.: 0343 - 4201351