mack - 4:48 pm on Jul 5, 2010 (gmt 0)
I did a little experiment with this today. I was close to a BT wifi zone, so disabled by mobile network, turned on WI-FI and enabled WI-FI as a location source.
To do this on an Android device you need to go to...
Settings > Location
From there check the box that says "Use wireless networks" If you read the text below that you will notice it says...
Location determined by WI-FI and.or mobile networks
I have disabled my mobile network. I them opened Google maps, no map could be displayed because my mobile network was disabled, and wasnt registered on the WI-FI network, but my location was shown on screen, and acuracy to within 50 meters.
Clearly WI-FI can and is being used and although not as accurate as GPS is could be useful.