Important to know, I suppose...<p>But if you are building a quick app or prototype, I've found frameworks like blueprint (<a href="http://www.blueprintcss.org/" rel="nofollow">http://www.blueprintcss.org/</a>) to be quite helpful.
If you need your columns to be equal height (eg: full-height backgrounds) try <a href="http://www.alistapart.com/articles/holygrail/" rel="nofollow">http://www.alistapart.com/articles/holygrail/</a>
For a quick overview / intro, this is excellent. Fast, to the point, and clean. I wish I had this when I started.<p>Of course, with only 9 effective steps of a single demonstration, it's rather lacking in completeness. But that's not its point, and I love all the links in this thread. Loads of good stuff :)
Step 11 should be: If you don't have an element to clear out the bottom, you can get limited functionality by applying<p><pre><code> overflow: hidden
</code></pre>
to the containing element. In most cases this will cause it to extend and prevent the inner elements from bleeding out. In some edge cases it will cause them to be hidden, though.
Yay! Just what the readers of Hacker News love to read… basic CSS tutorials! Can we have a "how to get amazing mouse cursors with JavaScript" one, too?