http://www.experts-exchange.com/Applications/MS_Office/Outlook/Q_21154050.html said:
There's a "Microsoft Office 2003 Save My Settings Wizard" in the "Microsoft Office Tools". That will allow you to 'save' and 'restore' all Office settings to and from a file. I tried it and it works fine for backing up email account settings.
The only disadvantage is that the accounts can't be saved separately. It saves all of them in one file (as well as any other Office settings, I guess). So you'd want to be careful that you're not overwriting recent changes when you use a previously backed up file.