Here are some links, if you want to learn more about it.

I posted this story, which sounded hopeful, here, last year:
http://www.journalstar.com/articles/2006/10/13/local/doc452eb9efc0fc6435...

And this, is from the National Sorghum Producers (includes some good articles):
http://www.sorghumgrowers.com/SORGHUM-to-Ethanol

Ethanol plants can play an important role in increasing local competition for grain, potentially improving prices paid to farmers.
* Ethanol represents the single largest value-added market for grain sorghum producers in the U.S.
* Ethanol consumes about 15% of the U.S. sorghum crop each year.
* One bushel of grain sorghum produces as much ethanol as one bushel of corn.
* There are currently 8 ethanol plants in the U.S. that use grain sorghum.
* Sorghum's low-water-use characteristics enhance the conservation benefits of ethanol.
* Ethanol from sorghum can replace MTBE as an oxygenate in gasoline, providing a cleaner, safer environment.
* When sorghum is used, distillers grain (an ethanol co-product) is equal in nutritional value to distillers grain made from corn.

The key here, IMO, is "Ethanol from sorghum can replace MTBE as an oxygenate in gasoline, providing a cleaner, safer environment." In other words, it is being used to fulfill the mandate, same as corn ethanol.

If you read about the process, they tend to gloss over the energy intensive logistical problems, requiring more research. EROI? It requires less rainfall than corn--that is good. Also, note that there are different types of sorghum discussed in these articles, short-grain sorghum, and taller sorghum being bred with little grain.

This is nothing new. It's been around for decades.