Found the issue.
Beta 2s stylesheet has been given updated radio button/checkbox css...
jQuerys blog mentions they have simplified the design, but usability has been sacrificed (at least I think it has!)
Adding this to your stylesheet rolls back the style gracefully:
.ui-radio-on, label.ui-checkbox-on {
border:1px solid #155678;
background:#4596ce;
color:#FFFFFF;
text-shadow:0 -1px 1px #145072;
background-image:-webkit-gradient(linear,left top,left bottom,color-stop(0,#85bae4),color-stop(1,#5393c5));
background-image:-moz-linear-gradient(top,#85bae4,#5393c5);
background-image:-ms-linear-gradient(top,#85bae4,#5393c5);
background-image:-o-linear-gradient(top,#85bae4,#5393c5);
background-image:linear-gradient(top,#85bae4,#5393c5);
}
Thanks
>Chris