"... a new app called Vtok will finally let Google Talk video chat users connect with friends on their iPhones — and soon, on Android mobile devices as well.
Vtok hooks into Google Talk, providing users with a list of all their contacts that are available for video chat and enabling them to initiate both voice and video chat calls. The app runs in the background and will send push notifications if someone tries to start a video chat with a user that’s logged in. Users that are signed in and receive call requests can choose to speak either by voice or video. Calls can be made or received on both Wi-Fi and 3G networks."
More info at vtokapp.com.