To change the Footer all you need to do is add the following snippet of code into the active theme's functions.php file.
// Change Footer in CMS
function remove_footer_admin () {
echo 'Powered by <a href="http://www.wordpress.org" target="_blank">WordPress</a> | Developed by <a href="#" target="_blank">Me</a>';
}
add_filter('admin_footer_text', 'remove_footer_admin');