I have MS Office 2007 on my machine, but I never use it - I use Open Office. I can't imagine why you don't think it's usable, or why you can't print an envelope.
Click Format/Page
Select the type of envelope from the dropdown.
Select the orientation: portrait or landscape
set your margins
click ok
Type in the address and print.
You can of course save the layout as a template for future use:
Delete the address
Click File/Templates/Save
Give it a name, click OK
To use the template, click File/New/Templates and Documents
Click Templates on the left
Double-click the template name on the right