Think this one speaks for itself :)
//Get via name attribute. Would be better if you added form ID to selector
var checkBoxes = $("input[name=" + checkBoxName + "]");
//Need to use each or you'll only get the first match
$.each(checkBoxes, function() {
if ($(this).attr('checked')){
//do stuff
}
});
//Get via class name. Would be better if you added form ID to selector
var checkBoxes = $('.' + checkBoxClass);
$.each(checkBoxes, function() {
if ($(this).attr('checked')){
//do stuff
}
});