There is a guy on the Gluten-Free brewers, Bluffwallace, who most definitely has experience with raw sorghum. Coincidentally I am getting 30# shipped to me either tomorrow or friday. I will probably malt some of it and roast the rest. The biggest fear, in my reading, is that cyanide is produced in the rootlets and acrospire and must be removed prior to consumption BUT, since they will only be used for mashing, I don't know how that will carry over...well anyways, what I malt I will do my best to remove these parts.
Check here too: http://www.homebrewtalk.com/f164/im-malting-away-gluten-free-sorghum-30036/