Andii helpfully points to the UK Just Church site.

Just Church is a free programme for use by churches, Christian groups and ecumenical bodies. It’s designed to help you embed a concern for poverty and social justice issues in the life of your community.

It looks like it’s well supported by various church and para-church organisations. The course material can be downloaded free, though printed copies are available for a small fee (and there’s a DVD you can buy with additional material, such as video, to supplement the base course materials).

There’s also a (free) package for doing a Lenten series using the materials. Definitely worth checking out for a look.