imo.im adds voice calling between users to iPhone app

IM client imo.im has become a pretty popular alternative to IM+ and its ilk with 700,000 active users daily making 500,000 messages. The service, which connects to multiple networks including Skype, Facebook, Google Talk, Jabber and more, is available on Android, BlackBerry, iPhone, iPad and Nokia.

Today’s update for iOS brings native voice calling between customers using the company’s built-in social network. Launched earlier this year, users can claim a username and begin chatting with one another directly, or use a global social board (a la Twitter) for public posts.

The voice calling feature is not quite like Skype — you can’t call out, only between imo.im members — but it comes a few months after the Android version got the same feature. While it may not break much new ground, for the hundreds of thousands of existing users, having the option to call over text is a huge advantage over using an existing service.

Download imo.im for iPhone.