This is a long, but really good article IMHO.
http://www.renewableenergyworld.com/...story?id=51929
If you don't have 10 or 15 minutes to read it all, here are some points:

-Employing the land to soak up atmospheric carbon increasingly appears central to averting global climate meltdown, and may very well depend on the skill of farmers and foresters in growing soil carbon.

-Studies highlight the need to direct biofuels growth in sustainable directions, using feedstocks that minimize competition for prime croplands.

-Biofuels done unsustainably could make the climate problem worse, while biofuels done sustainably could play a leading role in solving the carbon challenge.

-The choice is not between biofuels or not, but between sustainable and unsustainable biofuels.

-Growing populations that are becoming more affluent, especially in Asia, are well capable of driving up [food & fuel] prices on their own and are doing so. Land conversions as a result of corn ethanol demand could well take place even if corn ethanol was taken out of the picture. The timing might be a few years different, but the carbon releases would be the same, and without any balancing effect of biofuels displacing petroleum fuels.

-The great bulk of land conversions taking place today are for traditional needs of food, feed and fiber.

-Soybean conversions in Brazil are almost entirely driven by food demands.

-Supply constraints could push the price of oil to $150 a barrel by 2010. ( $112 today )
-These prices will drive demand for all sorts of alternatives including biofuels, and that will add to feedstock demand.

-With oil at $100 a barrel, distillers can pay more than $7 a bushel for corn and still break even. If oil climbs to $140, distillers can pay $10 a bushel.

-Economist John Urbanchuk notes that food prices are escalating generally rather than just in areas affected by increased corn costs, (due mostly to the price of oil).

-NASA Researcher James Hansen says humanity must now actively seek to soak CO2 out of the air. He points to improved farming and forestry practices as the most economical and feasible pathway to achieve this.
-Synergies between growing biofuels and biocarbon [sinks] could create multiple revenue streams that promote both.

-"Carbon-negative biofuels" - deeply rooted plants lock up more carbon in soils than is released in burning the fuels.

-Drawing new attention is combined production of bioenergy and charcoal, with charcoal returned to the soil. Charcoal buried in soils would retain at least half its carbon after 1,000 years.

-Six large-scale pilot cellulosic plants will be operating within several years. These plants will all employ waste streams, including municipal waste, wood waste and farm residues.

-The people who work the land might well save the world by useing the soil to meet our diverse needs for food, fuel, feed, fiber and carbon storage.