Dear Lost Sheep,
Hallelujah that you found Subcomandauntie. The websites thou describes are of the old, scary and cult-like left. But forget that "there's no room at the inn" crap; there are lots of radical church groups doing good work out there. You didn't say whether you are Catholic, but Subcomandauntie says Amen to the international (and anarchist) group Catholic Worker. Founded by journalist Dorothy Day and philosopher Peter Maurin in 1933, it originally promoted the biblical promises of justice and mercy. Maurin and Day opened a "house of hospitality" where the homeless, hungry and forsaken were always welcome. Nowadays their God-loving anarchist successors protest against injustice, war and violence in all forms.
Similarly, Church Action on Poverty is currently tackling the exploitation of migrant workers by gangmasters, and also dabbles in asylum-seeker rights.
And you may find a niche in the peace movement. Pax Christi, for example, is a radical Christian anti-war group that believes in social justice and non-violent direct action.
Then there's always the Quakers. But Friends' worship meetings may not be for the gregarious: Quakers meet in complete silence.
But do steer clear of the Christian Socialist Movement. It's shamelessly affiliated to the Labour Party: even the prime minister is a member, and leading patron rev Leslie Griffiths just slithered into the House of Lords.
Subcomandauntie's message to them is: God is watching.