Word 2003 Forms/Drop down boxes

I've been asked to create a form in MS Word. They want to be able to choose a plant location and then have an address box be automatically populated. Is there a way to capture the variable chosen in a drop down box and use it in this way? My co-worker is a VB programmer, but he only knows how to write VB code that will create a Word document, but not how to pass a variable to VB and then pass back data based on that variable?