My paper "Computing Mechanisms", which articulates and defends an account of what it takes for physical systems to perform computations (in the sense of computability theory and computer science), has been accepted in Philosophy of Science.  I will go over it and revise it one more time before sending the final version to PoS within a couple of weeks.  If anyone is interested in giving me comments before then, they would be appreciated.  Although a version of the paper is available on my website, the current version is slightly revised relative to that.  So if you'd like to see the current version, please contact me.

PS: Tomorrow afternoon I'm going to IJCNN2007 for a week, so if I don't get back to you for a while, that's why.