Google Talk is one of the most popular video chat clients for Android and shares some tight integration with Google’s own Gmail clients for communication. Many people even use Gmail as a pseudo-phone replacement. According to Google’s own blog, it looks like they’ll continue to push that calling feature set by letting you make free calls to the US and Canada throughout 2013. There’s no Android app for this yet, but hopefully this is a sign that Google’s willing to push to make that happen.
source: Gmail Blog