Which Template did you use? The normal Publishing site has the search  Scope
dropdown on the main page. Or are you asking how to get a scope  to show  in
the dropdown? To do that you need to add the scope to a display group on
the site where you want to use it. Go to Site Settings>Search Scopes and
you should see the scope under Unused Scopes. Edit the existing display
groups to add it to the dropdown  list.

I used the stanard publishing  portal. I did add a new scope  and
found it in unsed and moved it into a new display group. I just dont
see it being display. Wonder if it is somethig in the master  page?

Do you not see the drop  down or don't see the scope  in the drop down? The
dropdown is there normally in that template. If you modified the master  you
may have accidentally removed the dropdown. To see you scope in the
dropdown you need to add it to the existing display group for the dropdown.
There is one for the dropdown  and one for the search  center as I remember.
If you added it to a new display group that won't add it to the Scope
dropdown on the home page.

I just added a collobration site that was associated with the same
SSP and it does show  up. I have not modified a thing except
configuration options. Now that I see it working in a collboration
template, it must not be in the base publishing  template. I will
look at the master  pages available and see why it is not there.