Well, HTML isn't a programming language. It doesn't have any brains, as it were. It's just text markup (indeed, that's why it's called Hypertext Markup Language). HTML is incredibly simple, with the hardest thing figuring out the difference between inline and block elements. CSS is a bit more complicated (mostly with the way it handles element positioning), but the basics are simple enough.
Regarding resources, I'm not sure of any website that would meet my standards. Someone somewhere will no doubt mention w3schools, but that's a bad idea (see the w3fools link in my signature for the reason why). The vast majority of PHP tutorials available suck. They're either outdated, or they show exactly the wrong way to do things (like using 'global' everywhere). The best introductory resource I've found is Larry Ullman's Visual Quickstart Guide (http://www.amazon.co...ds=larry ullman). Easy to read, lots of pictures showing the exact code in action, and no glaring errors. Yeah, it's a book, which costs money, but it's the best introductory resource available, IMO.