easy...get a usb/serial adapter cable and connect the data "out" wire to the trio's data "in" - then make sure that the NMEA settings are correct - I believe that it will work on either 4800 or 9600 bps.
Robert "Smoke" is right on. Just make sure pin 3 on the serial db9 plug coming from the iFly is connected to the data in on the Trio. Pin 3 is data out and pin 5 is the ground from the iFly. Your Trio probably just has individual wired for data in. Then just match the NMEA settings and baud rate. You can even hangar test by setting the iFly into Simulation Mode. Hope this helps.
Actually, alot of radio shacks, electronic/computer stores stock them. I also believe that they are available on this site