scripts.php

<?php
//First you register the script
//The parameters are (title, path, what the script depends on, version-leave this blank, in footer)
wp_register_script('GIVE-IT-A-UNIQUE-TITLE-HERE', get_bloginfo('template_url').'/js/skrollr.js', array( 'jquery' ), '', true);

//Then you enqueue it (so it renders on the page)
wp_enqueue_script('skrollr');