For my library class, I have had to complete three courses on codeacademy.com. These interactive courses are free, though you can get a premium account and get a certificate and more detailed instruction.
We had to do the first courses on HTML & CSS, a style sheet language, Building a Website and SQL, a database. The courses were well designed with a good mix of theory and step by step instructions. Code Academy did have some bugs, which get fixed if you report them. I had problems with the exercises. When there were two tasks and I’d complete one, I’d get an error message for not having done both lessons even though the second task is darkened so you can’t do it till you’ve run the first. It was a minor annoyance.
While I prefer Lynda.com courses because they have more insider information and more of a human feel, Code Academy is a good place to get your toes wet to see if you want to learn more.