In the setup dialog for the Like-Button, there are only two options for layout:
Unfortunately, the numbers
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;
}