Here is the solution that works for all browsers (also IE7 and IE8; didn't check for IE6):
http://jsfiddle.net/RkvAP/230/
HTML
<div class="toggle">
<label><input type="radio" name="toggle"><span>On</span></label>
</div>
<div class="toggle">
<label><input type="radio" name="toggle"><span>Off</span></label>
</div>
JS
$('label').click(function(){
$(this).children('span').addClass('input-checked');
$(this).parent('.toggle').siblings('.toggle').children('label').children('span').removeClass('input-checked');
});
CSS
body {
font-family:sans-serif;
}
.toggle {
margin:4px;
background-color:#EFEFEF;
border-radius:4px;
border:1px solid #D0D0D0;
overflow:auto;
float:left;
}
.toggle label {
float:left;
width:2.0em;
}
.toggle label span {
text-align:center;
padding:3px 0px;
display:block;
cursor: pointer;
}
.toggle label input {
position:absolute;
top:-20px;
}
.toggle .input-checked /*, .bounds input:checked + span works for firefox and ie9 but breaks js for ie8(ONLY) */ {
background-color:#404040;
color:#F7F7F7;
}
Makes use of minimal JS (jQuery, two lines).