Simon Willison has an excellent tutorial on Defeating IE5 CSS Bugs. Good stuff.
Read the article, and also read these accompanying articles:
* "Owen Briggs Text Sizing Article(with LOTS of screen shots)":http://www.thenoodleincident.com/tutorials/box_lesson/font/
* "CSS Wiki":http://css-discuss.incutio.com/?page=ToHackOrNotToHack
* "The Box Model Hack":http://www.tantek.com/CSS/Examples/boxmodelhack.html by Tantek Celik
* "W3C CSS Specificity Rules":http://www.w3.org/TR/REC-CSS2/cascade.html#specificity
Interesting side note. When a CSS(Cascading Style Sheet) is listed shorthand as margin: 1em 5px;, it is applied to the top and bottom (first set), and then left and right (second set). I always have set out the four rules myself. (Top, Right, Bottom, Left).