I just bought HTC incredible S. It has front camera. How can begin gmail video chat?
This is now possible (May 2011):
Check out the demonstration video.
Note that this is available only for the
Nexus S for now, but it should soon work for all Android 2.3 devices.
The service is not available yet for Android devices:
Voice and video in Gmail only works with the newer version of Gmail in supported browsers: FF 2.0+, IE 6.0+, Safari 3.0+, and Google Chrome.