Just Cause Cheats
After you kill the man on the boat and finish the mission, you will get the agency jeep.
After level 2 there are territories you can take over. Once you have done about three of them you will get the grapple hook.
Taking over sites
Use the following trick when you are taking over a village with the guerrillas. Ignore most of the enemies and charge towards the roadblock the government has up. Destroy it using grenades, a rocket launcher or timed explosives. Do this to each one, and the "Capture enemy flag" objective will soon appear. Rush to it and press A to conquer that...
Boarding the President's plane
When you are flying the jet in the final level, fly over the top of the plane. Try to hover over one of the wings or the front of the plane (recommended). Quickly jump out of the jet and let go. If done correctly, a "Jump to vehicle" icon will appear. Quickly press A and he will grab on. You will immediately appear in the plane.
When you get your grapple hook fire it at a passing or attacking helicopter. Then, just reel your self in.