There’s finally a Google-endorsed reason for having the front-facing camera in the Nexus S: Google Talk with video and voice chat. The next OTA update to the Nexus S will be Android 2.3.4 which will have the feature built in.
The Google Talk video chat will work with anyone else with Android 2.3.4 and a front-facing camera, as well as anyone using Gmail with Google Talk on a desktop or laptop. Presumably Nexus One users, and other without front-facing cameras will still be able to use the voice capabilities of the service. The best part is that Google Talk video and voice can be used on WiFi as well as 3G and 4G, assuming your carrier allows it.
Android 2.3.4 will begin rolling out to Nexus S phones in the next few weeks. Presumably the Nexus One would follow shortly after the Nexus S. Other phones, as always, will be subject to manufacturers and carriers.
Read [Google Mobile Blog]