How to add drop down menu's to Nav

Hello,

I know this is kind of a newbish question, but I am trying to implement drop down menus with links to different pages to my navigation image buttons. Would there be an easy way to do with without all the fancy CSS or Java Script. Could there be a plugin out there that you simply apply to these images and it creates a drop down for each image?

If there really isn’t an easy solution could someone provide me with proper instructions on how to do this?

My website is http://www.managersareheroes.com/

The buttons I am talking about the the big red ones. Hard to miss. 😉

Thanks!