Within Outlook you can set up a rule that will apply to all sent messages to CC the message to another email address. To do this, go to Tools > Rules and Alerts. Create a New Rule. Select the option to Check messages after sending. Don't put any checks in the Select Condition list. In the Select Action list, check "Cc the message to people or distribution list", and select the email address you want to CC it to (you may have to create a contact first). Then hit Finish.

Note that this process isn't very discrete. The CC address will be visible by both the sender and the recipient. If you want to hide the extra address from the recipient, you'll need to have the message BCC'd. Outlook is not able to do this natively. There are some add-ins that can accomplish it, though. Here's an example:

http://www.ablebits.com/outlook-blin...dins/index.php

Hope this helps.

-SW