I helped create a video series, Using Organic Groups for Drupalize.me, and created the OG Extras module to make the 7.2 version of Organic Groups easier to use. We use that module in the video as an easy way to organize the group pages.
The series starts from the basics and goes through the various requried modules used to build a site with Organic Groups and then gets in depth with creating groups, adding content to groups, and dealing with group membership.
In addition to the basics of creating groups the series also takes a look at the various settings related to both access control and permissions and how you can combine them to create private and public groups. How to use the OG Extras module to display more information on the main group page and then how to use the Panels module to display group content and other advanced Fields and Views configuration related to OG.