IP address only appears when mouse cursor is on top

[onetwothree]

How do I make the IP address in the threads to only appear when I move the mouse over it?...similar to the the administrator's threads screen, ie: the IP address only shows up when the mouse cursor is positioned over the small PC icon. I still want the IP address available to the users (to prevent abuse) but I don't want the IP address shown so readily on a threads list that someone can print the page out with all IPs shown. I prefer that the IP only appears when he moves the mouse cursor over it. I hope it's a matter of inserting some commands in the templates. I'm no php expert. Thanks in advance.