Start with this article (http://brown-moses.blogspot.ca/2014/03/isis-deploys-croatian-weapons-against.html) about how Croatian weapons intended for anti-Syrian gov't forces are ending up in Iraq in the hands of anti-gov't forces.
But also go check out the videos / photos of them unloading Chinese ATGMs (http://brown-moses.blogspot.ca/2014/03/the-martyrs-of-mheen-brigade-arrives-in.html), and on Hezbollah's role in Syria (http://brown-moses.blogspot.ca/2014/02/special-report-on-hezbollahs-role-in.html)
lots at http://brown-moses.blogspot.ca/