How would you recommend to proceed to learn css?
Is there a great book, or online tutorial?
this is the best repository i know css 101
and some thing that bother most of us is floating
as far as books are concern i love "Eric Meyer" way of doing stuff, but some other worth mentioning books i read
CSS Cookbook by Christopher Schmitt
Core CSS by Keith Schengili-Roberts
hope that will help you getting startted
I am a big fan of CSS: The Missing Manual. It allows you to either start from the beginning and read through to the end, or open the index and answer specific questions on what you're doing.
The best way to learn anything is to do it. Make some web pages with bad CSS ("Why is my text always falling off the side?!?") and then look up the solutions (I like the W3Schools pages a lot, too). There's nothing like working through some bad CSS to give you confidence in working with CSS.
I also agree with the sketchbook - I keep one at home and one at the office. If you know what you want your page to "look like" it will become much easier to write CSS that matches your layout.