You are correct. It's an Add-In. You'll need to go to Tools:References and
select the Microsoft Office Web Components 11.0 library - then it will show
up in your control toolbox.
I think I've solved this problem, by the way. Apparently it's not a matter
of Excel 2007 not supporting the spreadsheet component. It's just not
"packaged" with the Excel 2007 install.
I went to the following MS webpage and downloaded the Office Web Components,
and then established the reference to the MS Office Web Components 11.0
Library - then right clicked the Control Toolbox - and the Spreadsheet
control was available. I've just configured it, and it appears to be working
OK.
So this issue is solved. Hope it helps someone else who discovers that the
spreadsheet control used in an Excel 2003 userform is kaput!
Thanks for your interest in helping, JJLGWhiz.