i want to recommend two wikipedia articles on New Kind of Science that i think are well worth reading to undrstand the research paradigm that SW is proposing.
http://en.wikipedia.org/wiki/A_New_Kind_of_Science
(i think this is an accurate description of the SW paradigm - reading the pages in NKS that deal with the role of modeling is also a good source)
http://en.wikipedia.org/wiki/Talk%3AA_New_Kind_of_Science
note: i'm not sure who authored tor subsequently modified these entries. the version of the first reference which i read a week ago included a very important point (not now included in the first reference above but mentioned in second reference):
"Wolfram is actually proposing in his book a discrete trivalent network [to represent the universe] because as he explains, finds the CA model unsuitable".
this is correct (SW is proposing the use of a causal net representation of the universe (an idea first proposed by Sorkin in 1987 (Phys. Rev., 59, 521 1987) but differrent from SW's view which treats - as best i can tell - time and space separately) rather than together as spacetime.
note: any review of NKS that states that SW views the world as a cellular automaton is simply wrong and throws doubts on any other claims in that review as to what SW states in NKS. and IMO any claim that the universe IS a CA or even a causal net is a bit ridiculous. i don't even know what that would mean (anymore than i understand what it means to say the universe IS a matheatical structure). SW has consistently stated that CA are USEFUL for modeling nature, not that it IS nature.
note to moderators: i hope you'll allow this to be posted. i am not attacking anyone specifically. i simply want to refer people to two articles where WL and Mathematica people can learn about NKS which has been IMO very unfairly maligned (personally i care far more about WL, the coolest programming language i've encountered, than the NKS research prrogram, and i think WL should be THE programming language of choice for both doing research in many fields of knowledge and for teaching programming to people and kids (i suppose kids are people too). it's too mad that the community doesn't seem to have a group specifically for NKS since i find the NKS forum and the Wolfram 'L'ibrary Archives to be less than useful and in the words of a friend essentially "a graveyard" for NKS and Mathematica writings.