Accept code input into Options Framework

A better approach would be to have the user simply enter their tracking script ID. You know, something like UA-XXXXXXX-XX?

Then in your header.php, output the standard tracking script:

<?php if ( $ga = get_option( 'google_analytics' ) ) : ?>
    <script>
        var _gaq = _gaq || [];
        _gaq.push(['_setAccount', '<?php echo esc_js( $ga ) ?>']);
        _gaq.push(['_trackPageview']);
        (function() {
            var ga = document.createElement('script'); ga.type="text/javascript"; ga.async = true;
            ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
            var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
        })();
    </script>
<?php endif ?>