The value of information is determined by value of changes in optimizing behavior. An overview can be found at http://ricardo.ifas.ufl.edu/aeb6182.risk/DynamicDecisionRules.html. Older material is available at
http://ricardo.ifas.ufl.edu/aeb6182.risk/Lectur19/index.htm
For a much less formal treatment, read NealStephenson's novel Cryptonomicon. The difficulty of assigning value to information is a recurring theme, from the problems of using intelligence information without revealing your source, to the potential value of very large numbers used as digital currency, and even the theoretical worthlessness of the exact location of a pallet of gold bars sitting unknown and unguarded in the Phillipine jungle. ISBN: 0380973464 . --GlennVanderburg