Running a calculation based on a drop down list

My office is stuck using excel 2002 for the foreseeable future. I'm trying to create a drop down box. I don't think validation is gonna get the job done here because I don't want anyone to type in the box. I just want them to click on it, pick an item type from the list (lbs, cubic feet etc) and then type a number into the box next to it. I'm building a conversion chart that will apply a formula against the number based on what item is picked from the drop down list. But first things first.

Can anyone tell me how to build a drop box / drop down list of static choices in 2002?


Thanks for reading my post.
-Mogul