If you do overflow:hidden
then keep in mind that it will also hide the comment box that comes up in XFBML version… after user likes it. So best if you do this…
/* make the like button smaller */
.fb_edge_widget_with_comment iframe
{
width:47px !important;
}
/* but make the span that holds the comment box larger */
span.fb_edge_comment_widget.fb_iframe_widget iframe
{
width:401px !important;
}