This "Butterfly GPS" device was built with an ATmega169 microcontroller, a GPS receiver board based on the SiRF chipset, and an LCD screen that reads out the data in real-time as location, date and time. Very simple construction and nice details on how it was built at the PDF link below.
A Butterfly GPS (PDF), [via]
http://blog.makezine.com/archive/2008/05/butterfly_gps_shows_you_t.html