$('.mySelect').change(function(index, elem){
var myFilter = $(this).val();
if(myFilter !="selectOne"){
var size = $('.qSelect').not(this).not(function(index){
return $(this).val() != myFilter;
}).size();
if(size > 0){
alert("already selected.");
} else {
// do something
}
}
});
$('.mySelect').bind('change', function(el) {
var _this = $(this),
newVal = _this.val();
$('select.mySelect:not([name=' + _this.attr('name') + '])
option[value=' + _this.data('oldVal') + ']').attr('disabled', false);
$('select.mySelect:not([name=' + _this.attr('name') + '])
option[value=' + newVal + ']').attr('disabled', true);
_this.data('oldVal', newVal);
});