When you print a message in Outlook, your name appears at the top of the printout. To change it you need to change the display name in your default account. If this doesn't work after a reboot, you'll need to create a new profile and use the display name you prefer in the display name field. (Exchange mailbox users can't change the name on their accounts, an admin would need to do it for you.)

You can try Outlook Printer (http://www.outlookprinter.com) - it takes care of some of the goofy ways Outlook handles printing and gives you some control.