how do I replace the fuel pump on my 1997 fiat punto 60 s?

Not to be attempted lightly, fuel will spill as you have to remove pump from it's housing INSIDE the fuel tank. Get a haynes manual if you are attempting it yourselves at home.
Lift up the back seat. Lift up the carpet under the back seat. Remove plate with screws holding it down. Top of fuel pump housing now visible. Up to this point you can back out of it with no problems if you are in any doubt whether to attempt it. If you are going to proceed - disconnect battery. Remove outer rubber pipes very carefully from plastic inner pipes, fuel if still under pressure WILL spurt, have rags ready to mop up and DON'T smoke anywhere near the vehicle (it has to be said for the minority out there). Remove wiring plug. Twist large black outer ring anticlockwise and remove. Remove housing from fuel tank, again very carefully upwards and outwards. This also doubles as the gauge sender unit. Very expensive to replace if it gets damaged. Fuel pump is now visible as part of this assembly. Disassemble it from the pipes and wiring. Reassembly is the reverse of the above. Make sure all seals, joints and wiring are secured and free of leaks. Turn on ignition without starting the engine & you should hear the pump run and prime the system, check for leaks. Any doubts book it in with your local garage.

MOT Andy
December 2006