>>890728>microUSBmeant microSD.
GPS has a mini-USB connector on it (digital-camera type connector, not phone-type connector).
A 4GB µSD card is *more* than enough for CityNav North America (US/Canada/Mexico streets, routable, with POI's) and US 24k topo. I backup track logs to the card, keep soft copies of the owners manual on there, bunch of other shit, and I think i'm still only around 3.5GB. I've got a 16GB in there now, it'll support modern-sized cards.