Go to the start menu and select ?enter cheats? then enter these cheats:
Superman: B, B, X, A
Team Superman: B, B, X, B
Autowin: B, B, X, Y
Refill ammo: B, B, X, X
Hint: Tree Top View in Lost Convoy:
In lost convoy multiplayer mode for Xbox live, you can climb up onto a tree branch in sector C3. Approach the tree slowly while looking up at the branch (there is only one tree in that sector) and you will pop up onto the branch. From here you can snipe players trying to get into the swamp.