http://www.freetech4teachers.com/2013/05/5-things-i-like-about-building-pln-on.html#.UcH2P6zVDL8

Here are some "How To Videos" on using Google+

http://www.freetech4teachers.com/2013/06/four-google-how-to-videos.html?utm_source=feedly&utm_medium=feed&utm_campaign=Feed%3A+freetech4teachers%2FcGEY+%28Free+Technology+for+Teachers%29#.UcH1CazVDL8

Here is a blog article that was written by a teacher who is working with teachers about making their own PLN's. This is another option, other than using Twitter.