I guess my question is whether the table tags themselves are sufficient to decide what is "column 1" versus "column 2". That is, is there an overarching table with two cells?

  <table><tr>
  <td> ... all stuff in column 1 ... </td>
  <td> ... all stuff in column 2 ... </td>
  </tr></table>
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If not, then you'll have to be pretty careful about the discriminator, to make sure all the column 1 stuff is cordoned off from the column 2 stuff correctly. If you have colspans that go across the column 1 / column 2 boundary, it will be pretty tricky. Otherwise, counting colspans is not that difficult.

In either case, you will probably end up using HTML::Parser or HTML::TreeBuilder or other generic HTML tree parsing helpers, and then playing with the parsed tag entities to collect them into separate components. Then, of course, you can output these elements in whatever way you want.