http://freethoughtblogs.com/butterfliesandwheels/2012/05/bishops-v-girl-scouts/
First, I know there's a rule saying that you're not allowed to quote an entire article, but I'm not sure if there's one about posting just links. I think you have to at least make some comment about your thoughts on it, but I'm not sure. Either way, I find topics consisting of only links and no explanations a bit irritating.
From what I gathered about on other articles about this (this article doesn't explicitly say, just that they're worried about "conflicts with church doctrine"), their grievance with the GSUSA is, surprise surprise, their stance on sex education and contraception, though the GSUSA say they have no official stance.
As for the article itself, I still find it amazing that they try enforcing their standards on organizations that they have no say in (unless the Girls Scouts is affiliated/funded by the Catholic Church and I just don't know it), especially when they know that they're under scrutiny of much of the non-Catholic word, and even many fellow Catholics.