Duplex printing in Outlook 2003 is broken and pages are not printed as you would expect them to be for booklets. This is expected to be fixed in Outlook 2003 SP2 but if you can't wait for the release of SP2 later this fall, you can call for the hotfix.
More information about the hotfix is found in //support2.microsoft.com/kb/892404
Not sure how to get a hotfix? See Tip 191: How to get Hotfixes
Published August 11, 2005. Last updated on May 8, 2014.