Using a list Box

I am going nuts.
How do I use dhtml to move items in a listbox control. I am familiar with the options collection but can not see how to move the items around with either vb or java script. If I have a list with the items: mike,joe, carol.
When I select carol and click a button I need for her name to appear second in the list. Basically I want the selected item to move up in the list. Then I have another button to move items down. I want full
control to move items up and down and order the list this way.