One way to have a report prompt the user for criteria before it runs
is to open a form from the report's Open event. Open the form in
Dialog mode so that the report waits for the form to be closed or
hidden before it proceeds. That way you can collect criteria from the
user and build a Where clause for the report. It also means that you
can call the report directly - you don't need to call it from a form.
And the selection form is reusable - it can be called from multiple
reports if they need the same criteria.

I've posted examples of this technique on our J Street Downloads page
at http://ow.ly/M58Y
See "Report Selection Techniques".

Armen Stein
Microsoft Access MVP
www.JStreetTech.com