I almost missed this one, but Sitepoint.com has published an article about CSS 2 positioning: CSS Positioning Properties At-A-Glance Guide.

By Nigel Peck: “This article is aimed at experienced CSS developers who need a reference for the properties related to positioning in CSS 2. Each section of this article includes a link to the relevant section of the CSS 2 Specification.”

A nice article that summerises what can be found in the W3C Cascading Style Sheets, level 2

CSS2 Specification
concerning CSS Positioning.