Julia said:
since the RxD and TxD pins are connected to the microprocessor directly. TxD and RxD are standard inverted serial signals with 3V voltage swings.
Use a ATMEL microcontroller that is powered at +3V supply voltage and connect the GPS RxD signal directly to the TxD pin of the microcontroller and GPS TxD to the RxD pin.
i.e. cross the connections on RxD and TxD between the two interface.
With a bit of programming you can communicate with the module. You still have to setup the correct baud rate between the two interface (which involves setting up timers etc... inside the ATMEL chip) and use the correct frequency crystal for the microcontroller in the first place.