Sounds like you are refering to Validation. As you are wanting a drop down list I would recommend highlighting K1:K100 (or any other range) and the naming it "MyRange". Include some extra rows in the range so that your Validation list will expand automatically if you happen to add more entries. You will see what I mean in a minute.
1. Select cell A1. Go to Data>Validation. Select "List" from the "Allow" box.
2. In the "Source" box type: =MyRange. Make sure the "Ignore Blank" and "In cell drop down" are checked.
3. Click the "Input message" tab and type a message if you want one to appear whenever A1 is selected.
4.Click the "Error alert" tab and type a message if you want one to appear IF a entry that is not part of the list is typed in the cell.
5. Set the error alert level from the "Style" box. Now click OK and we're done!
Select cell A1 and you can now pick from your list.
Type another entry in the named range and it too will become part of your list. This is why I suggested including some blank cells.
Hope this helps.
OzGrid Business Applications
Thanks a lot for the help Dave, I'll try it today