Access 2000 Report Question

I am using Access 2000. I have created a report in access that lists all employees and is sorted by department. This report is based on a query that uses [] for department name and prompts the user to enter in the department for the appropriate report.

What I would like to do is create a form that contains a combo-box that lists all the departments, and a button that will print out the department report based on what department the user selected from the combo box.
I have got everything set except for the code for the button. Help!!