Questions about GPS

[yuan_you]

I've a few questions about Treo pro's GPS:
1) It's a "traditional" GPS getting data from satellites or it works with GSM towers ?
2) it's always on and consumes battery ? if yes, how can I turn it off. or it's off automatically when the navigation software is closed ?
3) How does QuickGPS work ? it retrieves what kind of information from Internet ? How it can know where I am if I'm at a location where there are no satellite signals ?

Thanks.

Yuan