The main website for code is
http://www.w3c.org - may be a bit involved for the beginning, but it's good to browse through when you're looking for ideas or something difficult to find.
The book series "In Easy Steps" has books both for XHTML and HTML. They are great resources to have on hand.
I'm currently learning from a book "Professional Web Design: Techniques and Templates" for CSS and XHTML. It's more involved, but very good.