Connecting external data storage

Hi all,
I'm new in electronics so please help me with your advices. I'm trying to create auto pilot for car. I have GPS, few servos to control rudders and arduino diecimla. I don't know how to provide my car with the coordidantes. I know that i cannot plug the USB pen, because arduino USB is not real USB. So what should i for external data storage. I need simple solution for end user. That he could easily connect data storage to computer, write desired coordinates and plug the device to arduino. I don't need a lot of space. 1MB it is enough for me.
Sorry for poor english, but i hope u got the idea waht i need:)

SDcard
There are exemples (and even a library) for accessing an SDcard from the arduino.
Cheers

It would be great, but what about resources required to write to SD card. i hope it doesn't require my whole arduino memmory?

Have you seen the GPS Shield?

http://www.ladyada.net/make/gpsshield/