All cheats of RCT also work in RCT 2:

Name a guest as

Chris Sawyer        He will walk around taking pictures
John Mace           He'll pay double prices on rides
John Wardley        Create a guest that constantly think "wow !"
Katie Brayshaw      All visitors will wave
Melanie Warn        Increase the Guest Happiness
Simon Foster        He will walk around painting pictures.
Damon Hill          Drives go-karts twice as fast
BigBucks            Unlimited cash
Tony Day            Eats lots of hamburgers
Michael Schumacher  Rides four times as fast :p
Tom Cruise          Visits all attractions
Bill Gates          Unlimited money for all visitors