yourlabelid.Attributes.Add("onmousemove","abc();")
<script type="text/javascript" language="javascript">
function abc() {
var v = document.getElementById(<'%=yourlabelid.ClientID%'>);
v.style.backgroundColor = "red";
}
</script>
private void panel1_MouseHover(object sender, System.EventArgs e)
{
yourlabelname.ForeColor=SystemColors.ControlText;
}