Sorry, I actually write about this web site yesterday,
but my blog missed up since I wrote HTML code to my article.
The website explains about CSS and table with detail .
I think this is the best website for understanding XHTML because the developers of CSS+XHTML made the site.
I really recomand you to type the code by yourself because Dreamweaver missed up a lot.
Also, to use CSS you have to know about the HTML code.