You can't do that in OS X either on the desktop anyway. In Finder windows you can put things into the side bar on Panther and above, and you can use the column view as well which is damn handy... Windows has the considerably lesser List view which puts text descriptions on the side... But the desktop icons always have the text underneath. With KDE or GNOME on *nix, you could probably hack the source to make it work like you want, but that's as close as you're going to get.