personalización de radios mediante CSS. de @zmencay

gistfile1.css

input[type=radio] {
  position: absolute;
  height: 26px;
  width: 26px;
  opacity: 0;
  filter: alpha(opacity = 100);
  cursor:pointer;
}

input[type=radio] + label {
  display:inline-block;
  height:26px;
  padding:0 0 0 30px;
  background:url(../img/sprite-radio.png) no-repeat 0 bottom;
  cursor:pointer;
}

input[type="radio"]:checked + label {
  background-position: 0 top;
}