The MK4 Design Team hosted an on-line chat on IRC today. Ed Boon, Dave Michicich, Tony Goskie & Josh Tusi all showed up to answer questions. There the secret menu code for the Playstation & PC were revealed to the public. If you missed it....
PC MK4: Enter Kode: 312 203 , then PLAYER 1 should hold LOWKICK+BLOCK over the PRACTICE menu's DIFFICULTY setting for 10 seconds. Credit goes to Wargod for sending us this info.