• Brake. Brake once, don't pump or ride the brakes. This will only heat up the brake pads, potentially overheating them and making them fail. It will take more force than you're used to to make the vehicle stop. Use both feet if you need to.
• Shift. Move the gearshift into neutral. If the throttle is truly stuck, the engine will redline and make a lot of noise, but it won't be damaged. The injection computer will keep it from over-revving. Leaving it running will keep the power brakes an power steering working normally. Obviously, if your car has a manual transmission, simply stepping on the clutch pedal will slow the car.
• Steer. Steer your car to a safe place off the road and away from traffic.
• Pump the brakes.
• Shift into park. (Which won't engage at speed anyway.)
• Drag the brakes.
• Shut off the engine. (Well, shut off the engine as a last resort, but it may affect the brakes and steering, which will become heavier, although they'll remain operational.)
in reference to: Video on How to Stop Sudden Unintended Acceleration - Toyota Recall - Popular Mechanics (view on Google Sidewiki)