Corporate PGP for network operators

[Sean Donelan <sean () donelan com>]

Ok, extremely dumb question.  But I'm sure lots of other people have
already solved this one.

Network operators have been using various PGPs to exchange confidential
information for many years.  I have my own personal PGP key for my own
use and a nice Unix box of my own. There are licensed versions, freeware
versions, guerilla versions, and so forth.  NAI is no longer selling a
commercial version of PGP Desktop for Microsoft Windows/NT. Phil Zimmerman
points people to the OpenPGP  alliance http://openpgp.org/members/

What do commercial network operators, who are required to use Microsoft,
use for business PGP mail besides NAI?  I.E. if we need to exchange PGP
mail, what package is least likely to crash Outlook and Windows.