This site is helpful because it gives the coder basic information on each HTML element. It also allows you to try different examples yourself just to give you extra practice.
HTML Dog gives you practice guides to XHTML and CSS. So if you are a beginner, intermediate or advanced coder, this site tutors you through each step.
When you first click on this site you may think you have been directed to an actual source page but HTML Code Tutorial actually allows you to find exactly what code you need just by scrolling your mouse over the name. You are then linked to that specific code, making it easy to copy and paste and then make necessary changes.
Quackit.com is user friendly and gives you a little more than html codes. This site helps you with specific codes, generators and links for more than one specific website.