In the name entry screen enter the following:
roam01
or:
power01
(notice the zero before the one at the end of both words)
The first cheat (roam01) gives you access to all tracks in Mission Mode.
The second cheat (power01) gives you access to
SPM (Super Pursuit Mode) in all levels.
In fact you can also turn the cheats OFF, by entering:
roam00
or:
power00
(two zero's at the end of each word).
I'm afraid that's all there is..... there are no other cheats.
This is direct from Davilex by the way.