Google has just released official Google+ app for iPhone. The apps is free and is available HERE for download.
Google+ for mobile makes sharing the right things with the right people a lot simpler. Huddle lets you send super-fast messages to the people you care about most. And no matter where you are, the stream lets you stay in the loop about what your friends are sharing and where they’re checking in.
* Circles let you share the right things with just the right people.
* Stream is where you can get updates from your circles or see what people are saying about things nearby.
* Huddle is super-fast group messaging for everyone in your circles.