Use Skype or tons of other apps sadly. Or maybe use Google Plus Hangouts? I have not used them so hard to say if they work.
And from what I remember, video calling on Talk appeared on Gingerbread.
Google Talk with video and voice chat will gradually roll out to Nexus S devices in the next few weeks as part of the Android 2.3.4 over-the-air update and will launch on other Android 2.3+ devices in the future.
Downloaded Tango,Viber,Fring1.Tango- No IM option. Dropped2. Viber- Nice UI, No video call3.Fring-Requires registration, Audio,Video,IM all are available.Would test Viber and Fring for couple of days and use which turns out good.