I have been using this for as long as the UK SBS GUY site has been around (it is how the admin mails get to me at Microsoft), but when I went looking for the "how to do this" blog item, I could not find it.   After much searching of my blog I resorted to searching live.com and there was the article - not mine, but the one I used.

http://www.msexchange.org/tutorials/MF015.html

It is very common for some of your users to express an interest in having their mail delivered to a mailbox that is external to your organization. For example, the user is going to be working away from the office and would like their mail to be delivered to their Hotmail account. Another request might be to have their mail delivered to a different person altogether

So I can finally give them the credit they deserve.

ttfn

David