You can easily change notification on GTalk for Android when an Instant Message (IM) arrives, when you are invited to a voice or video chat. Change ringtone for video chat, and other notifications by doing as follows:
1. Open "GTalk"
2. Go to "Settings" by hitting "Menu Button"
3. Select the Account you want to change
4. Under "Chat Notifications", tap "IM Notifications" to specify how to be notified of arriving an IM: Open Dialogue, Show Notification, Off
5. Select "Notification Ringtone" to change the ringtone for arriving IM on GTalk
6. Select "Vibrate" to change vibration status. available options are: Always, Only When Silent, Never
7. To change the settings for Video Chats, tap "Video Chat Notifications" and select either "Open Dialogue" or "Show Notifications"
8. Select "Video Chat Ringtone" to change the ringtone and select "Vibrate" to change vibration status