Yesterday, Google announced that Gmail will have video chat and voice support. Actually, user will need to install an enhancement to Gmail that will allow the 2 new options. The Gmail voice and video chat enhancement (browser plugin) can be installed following this page.
While the feature will not immediately available for all Gmail users, we should see it spread across Gmail in the next 2-3 days. I personally checked my Gmail account and it seems that I can use this feature at this point, it’s possible that Google updated all the Gmail servers faster than expected.