Assuming you haven't already tried the keyfob button, and it didn't work....
Go inside the car, and remove the cover of the fusebox which is located below the steering column near the floor, and you should see a fuse that has a picture of a car with the front trunk open, pull on the fuse and it should come out, BUT NOT ENTIRELY, then attach the positive jumper to the outer edges of the fuse (where the metal is) and the trunk should open.
Discription of fuse box in 2001 Porsche boxter
The 2003 Porsche 911 has 24 valves.
The 2003 Porsche Cayenne has 32 valves.
The 2003 Porsche Cayenne has a V8 engine.
The 2003 Porsche Boxster has 24 valves.
The 2003 Porsche 911 is a gas-powered vehicle.
The 2003 Porsche 911 has a 6-speed manual.
The 2003 Porsche Boxster is a gas-powered vehicle.
The 2003 Porsche Cayenne is a gas-powered vehicle.
The 2003 Porsche Boxster has a 5-speed manual.
The 2003 Porsche 911 has a flat 6 engine.
The 2003 Porsche Boxster has a flat 6 engine.