I have completed the migration of CHT to use a 3 column dynamic layout using DIV's.  I haven't found many examples of this especially with ASP.NET.  I will eventually expand this into a full tutorial.

Advantages of DIVs vs TABLEs
You can find this someplace else but I want to emphasize the reason i switched to div's was for troubleshooting and ease of maintenance not standards compliance (but that's another upside).  I find that I can read through my HTML much more quickly and the div actually provides a semantic meaning to the content versus a bunch of nested garbled tables. 

Traps
The hardest part was making this dynamic.  For instance what happens when you only want a two column layout or a one column layout? 

Implementation
The key is using a panel control (actually 3 of them or more).  The ASP.NET panel control is actually rendered as a div (in most browsers, you may have to use the browser caps hack to get the correct rendering in all browsers but this is pretty easy).  Once you are working with divs then the normal CSS rules apply.  The secret is applying styles dynamically so that the divs can be resized based on whether they contain content or not.  This is actually straight forward.

I promise I will post the sample code soon.