http://www.cbsnews.com/stories/2001/11/09/national/main317573.shtml
http://abcnews.go.com/sections/us/DailyNews/abortionanthrax011129.html
There was an HBO special about the Army of God:
http://www.unaff.org/2001/f-soldiers.html
And they have their own website:
This was a simple google search.
There is no such group. That is it doesn't exist. It's been a common euphemism cited by a number of people who have attacked abortion clinics and abortion doctors, who have no connection whatsoever with each other.