I love learning by example with books that more or less talk to you like a actual person :] so I would not go with O'reilly personally. I am a huge fan of Wrox press.
When I started I actually got Hacking Myspace from Extreme Tech xD and it teaches you practices of CSS, and some HTML, its very basic, but it worked.
Then I picked up a real book that was definitely worth the coin (50.00$USD)
it was The XHTML, CSS, and XML Bible 4th Edition. Absolutely amazing book, and it makes one hell of a reference too. It shows you practices, no nos', extensive coverage on tags, their attributes, and a bunch on CSS2. Mind you CSS3 is coming about for new browsers so try and learn that, but focus on gettin the basics first!
Another book I would reccomend for everyone to read would be CSS mastery 2nd edition. Of course you need to learn CSS first though. I don't know how many times I say it but, CSS is a must :]
Other books (not exactly coding) I would reccomend for you later in your study would be:
Don't Make Me Think 2nd Edition
Designing with Information
Web Designers Idea Book
PHP Bible
Java Bible
and Designing with Standards 2nd Edition.
I would definitely get The XHTML, CSS, and XML Bible though, it is a great book.
Other resources may include:
http://www.w3schools.com/default.asp
http://www.developertutorials.com (they have nice guides, tips and more)
http://www.css3.info/
I hope you find this useful

good luck learning, feel free to ask any questions if you have any!