dual colums in a dropdown list

Does anyone have a quick reference how to make two colums in a dropdown list? I am looking to produce something similar to the way results are presetnted on Google Suggest (http://www.google.com/webhp?complete=1&hl=en) when you start typing in a search term.

If need be, I can look through all the code to find out how, but thought I would ask here if anyone have a link to it to save me the time.

-Greg