You'll need to find out what the baud rate is. Here's a nifty little trick. First make sure your grounds are connected between the boards, next download the sketch below and then locate the Serial Tx pin on the GPS. Connect a wire to the Tx (not the Rx) pin on the Arduino and then open up Serial Monitor. Cycle through the Baud rates on the bottom right corner until you see properly formatted NMEA data...now you know what the baud rate is. The only other concern is you'll need to know what the logic level of the communications is if you intend to send commands to the GPS. If it uses 5 volt logic then it won't be a problem reading or writing, however if it uses 3.3 v or lower logic then you should have no problems reading the GPS but you can't write to it directly without the use of a logic level converter.
void setup(){
pinMode(0,INPUT);
digitalWrite(0,LOW);
pinMode(1,INPUT);
digitalWrite(1,LOW);
}
void loop(){
while(1);
}
What this sketch does is turn your Serial port pins off and set them to a high impedance mode and basically takes incoming signals on the Tx pin and send them directly to the Serial Monitor. Also anything you type in the Serial monitor will be sent out on the Rx pin of the Arduino.
Good luck!