The way i handle the rs232-ttl conversion is with this little thing. Just strip the wires on it and connect it to the right wires on your GPS and your done. Hard pressed to beat the price even if you made one yourself too.
very cool. just ordered it. now, just need wait for it to arrive, make me a custom serial cable and get the balls to soder for the first time. then i will have gps on my empeg. heh.