Tom Philpott wrote an
excellent article in Grist that ought to be required reading for anyone who wants to take part in the organic food debate. Interestingly, the strongest part of his argument for organics is not their effect on human health (which he does argue, but which I think the evidence for is a little weak), but rather their effect on soil quality, and soil quality's effect on human health.
Good readin'.
Get to it.