Javascript - Eloquent Javascript; DOM Scripting<p>HTML - Dive into HTML5.<p>CSS - Books by Eric Meyer or Dan Cederholm<p>Sites: Quirksmode, CSS-Tricks<p>PHP and MySQL. Don't bother with either yet. You probably think you need to learn them due to popularity. You don't or at least probably don't unless you know you are going to be working with Wordpress, Drupal, Joomla or other PHP and MySQL based platform.<p>You're probably going to need HTML, CSS and Javascript. Stick to those technologies for the time being. Once you know them well enough, you should know enough to choose your backend stack. If you aren't working with a platform that specifically requires you to use PHP and MySQL, it's likely that you'll end up using Ruby, Python or Javascript on the backend given recent and current trends.<p>Even though it won't be sexy, learn javascript before jQuery.