While I was searching for a MUD based on the Matrix at Mudconnect, and in the process, I found a MUSH based on William Gibson's novel Nueromancer (they also took some ideas from several other novels and movies, but that is the main inspiration), and while I was checking out the Mush's (Chiba City MUSH) website here. There I found an interesting guide here, which is supposed to be a guid to the Matrix (not as in the movie Matrix-as in the MUSH's Matrix), which describes it in character as if a character from the game were talking with you about it.
I found it quite interesting that the Matrix described really isn't too different from the internet, and more interestinly how ppl (netrunners) break into other ppl's system in the Matrix is quite similar and symbolic as to how it is really done.
I think you ppl should check it out its really kewl....