You can use regular old javascript for that:

function isEmail(email) {
  var regex = /^([a-zA-Z0-9_.+-])+\@(([a-zA-Z0-9-])+\.)+([a-zA-Z0-9]{2,4})+$/;
  return regex.test(email);
}

if ($('#mtQuiz').length > 0) { // <- unnecessary and superfluous
    $('#myQuiz').validate({
        // options, etc.
    });
}

You're using jQuery so you don't need to check for the existence of #myQuiz with if ($('#mtQuiz').length > 0). If the #myQuiz element doesn't exist, jQuery will simply ignore it without any errors.

This is all you need to do...

$('#myQuiz').validate({  // initialize the plugin
    // options, etc.
});

To match the value of another field, simply use the equalTo rule. While using the equalTo rule, there is no need to duplicate any of the other rules since equalTo will always force the value to match the primary field's value which already followed its rules.

$('#myQuiz').validate({
    // options, etc.,
    rules: {
        'entry[first_name]': 'required',
        'entry[last_name]': 'required',
        'entry[email]': {
            required: true,
            email: true
        },
        'entry[confirm_email]': {
            //required: true,  // <- redundant, not needed with 'equalTo'
            //email: true      // <- redundant, not needed with 'equalTo'
            equalTo: '[name="entry[email]"]' // <- any valid jQuery selector
        }
    },
    // other options, etc.
});

DEMO: http://jsfiddle.net/JCY2E/

if($("#author_email").val() != $("#author_confirm_email").val())
{
alert("emails don't match, sucka");
}