I did this by using data attributes. Is a lot cleaner than other methods attempting to explode etc.
HTML
<select class="example">
<option value="1" data-value="A">One</option>
<option value="2" data-value="B">Two</option>
<option value="3" data-value="C">Three</option>
<option value="4" data-value="D">Four</option>
</select>
JS
$('select.example').change(function() {
var other_val = $('select.example option[value="' + $(this).val() + '"]').data('value');
console.log(other_val);
});