At the exit from the initial tunnel there are 2 ramps. Jump off the left one and the package is just after the cash items.
Its in the Right ramp at the beggining of the race
Behind a stack of crates on the right side of the track.
Directly behind a bride column on the road. I believe you'll find it after the first elimination. It is NOT on the beach.
In the middle of the first long left turn, there is a shortcut that goes by a windmill and some houses. There is a detonator powerup and the hidden package is right next to it.
In the snow section go left before the rock 'island' on the inside of the first sharp left turn, you'll find a ramp and the package
It's on the road, on the latter half of the course. It's in the middle of a circle of junk past the ramp with the nitro boost on top.
The hidden package on moon island elimination is behind the shed, in the 90 degrees curve to the right, before the beach.
go after the gas tank in the forest and you see a track in right side and you see a hidden package
in liberty city
up the bridge on the left
after coming out of the initial tunnel you pass a gas tank on the right. the hidden package is on the right shortly after passing the gas tank .
Near the beginning in a field on the right