Put briefly, it's a WWAN (Wireless Wide Area Network) router. In more human terms, it's a compact little box that gets data from cellular towers and re-shares it for multiple computers to use.--Tor AmundsonTo use it all you do is plug it in to the cigarette lighter of a car (or a 12v supply when at home). It automatically boots up and links in to Verizon's "Broadband Access" service, turning itself into an access point. Turn on your laptop, join the network and voila -- you're on the net! It's just like using a hotspot (such as they have at Starbucks and airports), but it goes anywhere you car goes.
Read all about it...
http://moro.fbrtech.com/~tora/EVDO/index.html