Google has started rolling out a new Gmail People Widget that will provide the ability to be able to view recent posts from the Google+ social network directly from your Gmail account. Once you have access to the widget any Google+ posts that have been sent to a circle you are a member of will show on the righthand side of your Gmail account. As in the image below. In the future Google may tweak these privacy settings when the Google+ social network moves from its current beta development stage to full public access.
To be able to use the new Google+ Gmail Widget you will need a Google+ account. The feature is currently being gradually rolled out by Google to Google+ members, so if you can access as yet just hang in there and be patient.