jQuery UI comes with handy icons in a sprite image; see the themeroller.
I have an input element for which I want the clock icon (with class .ui-icon-
input
.ui-icon-
$( "span").css({ width: 16px; height: 16px; background-image: url(images/ui-icons_222222_256x240.png); // change to correct location background-position: -80px -112px; });