Google Mobile uses undocumented techniques that are supposed to be off-limits to iPhone developers in order to make its verbal search feature work with an iPhone sensor.
shame on Apple for letting this through then, but I won't complain unless other developers are prevented from using the proximity sensor in their apps.
but it only held up release a couple of days. it's out there now, I have it. and it's very well done. I'd love to see what other developers can do with access to the proximity sensor.