You might not get them for free, but the e-books at www.sitepoint.com are world-class and definitely worth paying the few bucks for.
I recommend lynda.com it is not free of course but if you can afford it then it is an easy way to learn. There are a few good sites that I use for reference like w3schools. When I was learning I would also look around at other peoples sites to get ideas of how they do things. Web Designer Wall is a good blog as well as Tuts Plus.