Question: I'm admittedly favour DIV, but am working on a project that uses nested tables. I have a need to move some fields that already exist, and create new fields, into what I would describe as a grid (think gridview in .NET).

What is the most painless way to add columns to the nested HTML tables? Alternatively, should I investigate the idea of redesigning the whole page with a table-less design except for the fields I need in a gridview?

Gridview is something like this:

Columns: Qty, Amt, Notes  

Rows: Materials, Labor, Miscellaneous

Answer: 
You would have to add <TD> cells to each row.

Since you said you also need to move things around, you should consider re-writing the output structure to a DIV format or a re-written table structure. I prefer table structures for data grids, personally.
First off, i don't know what Gridview looks like...but...
If i understand the question correctly, you could try adding a `<td>` with a `<table>` inside it, then use that table as the column. When you are done with the column add in a `</table></td>` and things should be the same as before.

this method can get really messy though and im not 100% sure this is what you are trying to achieve.