To enable the video chat in orkut you need to install this small plugin from official page.
According to official orkut announcement:
Orkut is all about keeping people connected, and a lot of people use orkut’s voice and video chat to stay in touch. Lately, we’ve been hard at work making it work even better, and the reception has been so great that we’re giving voice and video chat a new home at the top of the chat window.
If you are an Orkut addict you will enjoy this new feature from orkut. Do let us know what do you think about this orkut video chat feature?