I had this probelm a while ago.  Keep in mind that you have to be using
Publisher AND Outlook 2006 in order for this to work. You also have to make
sure that Outlook is set as your default emailing program.  

If you just don't see the icon but suspect the feature works:
You might need to drag and drop the icon onto your File menu.  Go to 'Tools'
then 'Customize'.  Make sure category is set to File and choose the correct
icon.  Grab it with your mouse and hover over the file menu - it will expand
and drop the icon where you want it.

In my case none of these solutions worked.  In the end I checked for updates
and voila it was fine - somehow, even after 2 reinstalls it hadn't installed
correctly I guess.  

Hope this helps!
Ann