Briefly saw this article today linked from the W3C, it gives a bit of an overview on CSS, I didn't have a great look, but I think I will one day. Not working on web stuff this month.
CSS for layout is one thing I have never fully mastered, and I really would like to though. I just have never found any great resources, also I guess that the support for it in browsers has been pretty lacking.
The quan for me is to be able to provide an 'iframe' like embedded resource (with the vertical scroll bar) that was actually driven by content on the same page (i.e. not actually a frame with seperate HTTP request). I've sort of acheieved this, but only with some table hacks, and only works in IE.