Assuming you already know html, have a look at the CSS tutorials on http://www.w3schools.com/css/default.asp which should get you started.
Don't. Instead, I suggest you read either Build Your Own Web Site The Right Way Using HTML & CSS by Ian Lloyd (if you're coming from a table based layout mindset or are new to Web design) or HTML Utopia: Designing Without Tables Using CSS, 2nd Edition by Rachel Andrew and Dan Shafer (if you're comfortable with semantic HTML markup but need to learn how to use it with CSS). Either way, you should eventually pick up and read The CSS Anthology: 101 Essential Tips, Tricks & Hacks, 2nd Edition by Rachel Andrew.
Those won't be of any real good to the new Web designer since they're geared towards those who already know what they're doing instead of those who are just starting out.
yeah, but they sure are pretty - and a great source of inspiration (at least for me). another good thing to check out is the Blueprint CSS at Google Code (code.google.com/p/blueprintcss). it will teach you how to use a grid layout. grid design is a touchy subject. many designers believe that grids constrain your ideas, while others (typically those who came from a print background) believe it is sensible design. either way, grids provide a great starting point.
once you learn html, css shouldn't be that difficult just go to the library and grab a book or read about it online. Start small and work your way up (hint: its not that hard just try ) make sure your work is w3c valid also