I used to work for General Motors at their main proving ground in Michigan. In one of the safety classes they gave us one big rule when it came to fires forward of the bulkhead (as opposed to those in the passenger compartment).

#1 - The most important thing to do is pull the release lever (usually in the passenger compartment) as soon as possible, but don't try to lift the hood.

#2 - Call for fire fighters.

#3 - Stand well away from the vehicle.

I guess in the event of a fire the little clamp that fastens the cable to the hood latch tends to heat up and come loose. This makes it VERY hard for the fire fighters to pop the hood.

Trying to lift the hood yourself will likely get you seriously burned and only provides more oxygen to the fire. Let the fire fighters lift the hood when they are ready to douse the flames.