On centralized (bureaucratic) vs decentralized (market) allocation of water (and more!) at NOAA [MP3] and slides [PDF]
On land and water grabs in Africa at IFPRI [MP3 -- much better quality than what what callers heard] and slides [PDF]. During the talk, Ruth Meinzen-Dick provided these useful links:
The International Land Coalition probably has the best site on commercial pressures on land. They start with GRAIN listings but only add deals they can verify. Also check the World Bank land conference website (2 years of case studies and macro analyses) and the International Conference on Land Grabbing that took place in April 2011.
She ended with this caveat: "There is no way to distinguish between a land grab and foreign direct investment without micro level data on performance." I totally agree.