I'm still undecided, I have a bit of a doubt... I have a 2GB AT&T Data Plan for my cell phone (Android), can I just stick my SIM card in the VITA or I need a Exclusive Plan for the VITA?

Why wouldn't GPS work without internet connection?
I think you're misinformed. ;)

I use GPS with my car navigation regularly and that machine definitely has no internet connection.

here in Canada.

if they give you 30 dollars 6GB plan/months, Then I might consider it.

Oh, also take 200 dollars off on a 3 year plan please.

I bet you, in Canada, Rogers will be the 3G provider.

Is that because the map data are streamed?

... Then I understand. If the map data aren't stored on the machine, GPS won't work of course. I haven't thought of that before.

Thanks for the input.

GPS also needs present location data to work properly. The GPS satellites triangulate the device's position via the corresponding GPS transmitter/receiver.

Typically in dedicated GPS devices, the maps are stored on the device, requiring manual user updates as they become available, but they work faster than cell phone based "GPS" systems with streaming Google/Yahoo Map data that use the cellular network to pinpoint your phone's position, which from my extensive experience with the iPhone, is much slower and less accurate.  

Someone actually suggested that "GPS" can work by predownloading a map with directions (in essence, the same as pulling up a Google Map location to location search) that "still works" without any sort of incoming signal, whether GPS satellite signal, WiFi signal, 3G network signal, or cellular network signal, but in all seriousness, that's the same thing as saying a printed map generated by any device is "a GPS device that works without network connectivity." And it still doesn't give the user their present location.