So I'm sure you have seen the poster Xerographica on forums. If not, here's the dude's blog: http://pragmatarianism.blogspot.com/. Well, in the following essay, me and a friend disprove his position in full, with chiefly economic but also moral argumentation: http://libertariananarchy.wordpress.com/2012/03/08/hello-world/
You're out of date. Your stance here is based on the counterattack over the possibility of economic planning mimicking perfect competition. Hayekian information problems can certainly be used. However, within the context of market socialist, there is no reason that the price mechanism cannot be used.