To comply with Massachusetts's new personal information protection law, my company needs to (among other things) ensure that anytime personal information is sent via email, it's encrypted. What is the easiest way to do this? Basically, I'm looking for something that will require the least amount of effort on the part of the recipient. If at all possible, I really want to avoid them having to download a program or go through any steps to generate a key pair, etc. So command-line GPG-type stuff is not an option. We use Exchange Server and Outlook 2007 as our email system.

Is there a program that we can use to easily encrypt an email and then fax or call the recipient with a key? (Or maybe our email can include a link to our website containing our public key, that the recipient can download to decrypt the mail?) We won't have to send many of these encrypted emails, but the people who will be sending them will not be particularly technical, so I want it to be as easy as possible. Any recs for good programs would be great. Thanks.