I need it so that if I select the top item on the first list box it selects the first option on the other 10, and it does the same so that if I pick the 356th item on the list box, it pick the 356th item on all the other list boxes
The index method seems the way to go, the only addendum I have to it is make sure that you put it on a keypress event also (actually, if memory serves you only need it on a keypress event, but I'm often wrong) That way if your user gets ants in their pants and decides to scroll the box with up/down arrows, it will scroll all of them. The only problem I've encountered with this is that if someone decides to grab the scroll bar and move one box, the other boxes don't move. I like to see my highlighted line run straight, and while it will still highlight all the correct items, sometimes the line won't be straight if the scroll bars have been repositioned.
Don't listen to me.
P.S. The one by Bruce only allows the first list box to control the others, remove the If index = 0 / end if if you want all the boxes to control one another.