Learn CSS Positioning in 10 Steps

Indeed. A very nice tutorial, but the ID names are a perfect example of how not to name classes IDs

BrainJar: CSS Positioning

A clear, detailed overview.

The Box Model

explained with a nice clear image by Jon Hicks

W3Schools – The Float Property

An overview of the float property. Edit on the fly: float an image. basic home page with floats

Intermediate: floating in depth

Float Tutorial

Excellent step by step instructions for how to do basic useful things with floats — put an image on the right, create a navigation bar, make a drop cap — all the way up to complete 2 and 3 column layouts.

CSS Float Theory – at Smashing Magazine

What you should know about floats with additional links to various resources and explanations. The concept behind using floats for layout isn’t that complex. Most problems are caused by versions of Internet Explorer…

Clearing Floats

Boxes around floats don’t see the floated elements inside them, so the container boxes need to be told to “clear” the floats. This is a tutorial on clearing floats without having to use an extra non-semantic element (with additional help for fixing bugs in Internet Explorer).

Advanced: the IE nightmare…

IE Float Margin Bug

Doubled box margins next to a float on Windows computers.
Just one of the many many fun things to learn about the bugs of Internet Explorer…

On Having Layout

A extensive theoretical and practical essay on the concept of “hasLayout” in IE for Windows. Much of the irrational layout behavior of IE is due to this undocumented function built in to every version. Forcing an element to have “layout” is a magical way of making Internet Explorer act as if it were a web browser. Reading this essay is a way for you to decide if you really want to be a web developer.

a helpful pie chart:

time breakdown