I saw this yesterday over on the Make blog. Adafruit has come out with a new Arduino shield which looks excellent for UAV usage. The shield has support for several gps modules, and can log data to an SD card.
Even with the GPS and SD card, there are still 5 digital and 5 analog IO open.
Here are the details(text below lifted from adafruit.com):
GPS shield for Arduino kit with data-logging capability. After building this easy… Continue