The easy solution would be to use the up down selction code here, but that is not what you are looking for.
http://www.mattkruse.com/javascript/selectbox/ I am not going to write it, but basically you need to have an array with all of the names. You need to dynamically write the array's elements to the page using innerHTML of a layer. Each time a button is click you need to determine which radio button is selected. by looking at the radio button array. You then need to switch the two items based on what button was clicked.
Problem is, when the person comes back to the page they will be back to the default order.
Eric