There is no specific section in the APA manual about creating references for social media sites.
However, the APA Style Blog has multiple entries about citing various social media pages, such as Facebook, podcasts, Google+, Twitter or Wikipedia. Look through the various blog entries listed here: http://blog.apastyle.org/apastyle/social-media/
All information and page number references are based on the 6th edition of the Publication Manual of the American Psychological Association (2009/10).
Need a copy of the Publication Manual? Click here for details. See Also: APA Style Guide to Electronic References, Sixth Edition