Call to Action.
Catholics for a Free Choice.
The Anglican/Episcopalian Church.
Each of these claim to represent Catholicism, each in differing degrees. Call to Action claims to represent the disaffected, disillusioned, and disenfranchised Catholics turned away by the Church's refusal to amend Her ways. DignityUSA claims to support those with homosexual tendencies who cannot (a) live as a faithful Catholic and (b) leave the Church. Catholics for a Free Choice claims, like Call to Action, to lobby for a 'liberalization' of the Church's eternal teachings, and also claims to represent a large number of people. Finally, the Anglican/Episcopalian Church defines itself as Catholic, sometimes with a capital 'c' and sometimes with a lower case 'c' - clarity not being one of its most noticeable features.
Of all of these groups, the only truly honest one is, !quelle surprise!, the Anglican/Episcopalian Church. Sure, every Catholic is well aware of the history of the Anglican Church, and has a right to disagree with my opinion, but at least the Anglicans formally left Catholicism when its leaders couldn't find the energy to hold fast to the Catholic (notice the large 'c') Church. The other groups, thus, while claiming to belong to the Catholic Church, don't really in reality.
By separating oneself from the Church on certain dogmas (which strangely enough, always seem to have something to do with sex), one begins to enter into the realm of Protestantism. Protestants, you see, are the honest Catholics who once upon again for whatever the reason decided that life was better when you cooked up your own recipe for eternal salvation and realised that such a philosophy was incompatible with Catholicism, and left. Call to Action, DignityUSA and CFFC on the other hand, are sort of Protestants in transition. They believe Protestant things, but don't believe that they're Protestants.
The problem lay Catholics face when approaching people involved or snared by these groups is that there is, or at least there has been, little support from local Church hierarchy. As I'm sure many Catholics will agree, most bishops appear more concerned with stepping on people's toes and PR than working to improve the spiritual health of their diocese. But this is beside the point, for these groups are lay run and in some cases lay funded. It is the role of the laity to make sure these groups are not able to put any more people in jeopardy.
How can we do this? Discussion and prayer.