Liberation theology is a theological movement originating in Latin America in the 20th Century, which picked up Marxist critiques of society and integrated them into a theological movement that focused on the motifs of liberation and "God's preferential option for the poor." Also, some of them have funny names. Hugo Assman is my tip-top favourite liberation-theology-name, but today's theological thoughts come from Leonardo Boff (snigger), who identifies in his book "Jesus Christ Liberator" these key characteristics of a Latin American Christology:
The primacy of the anthropological element over the ecclesiastical
Boff says that Latin American theology values the human person over the structures of the church. The church exists to "help, raise up and humanise" people. The Church needs to be free to create new structures that allow fresh incarnations of the church.
The primacy of the utopian element over the factual
Latin American theology is determined by the future, not by the past: by hope for the utopia of a world fully transformed and made free from sin. The Church should be driven by its desire to see the kingdom of God come on earth.
The primacy of the critical element over the dogmatic
The Church's tendency is to become institutionalised and stagnant, but by reflecting critically on its theology and praxis, this doesn't have to be the case.
The primacy of the social over the personal
The Western Church has tended to make salvation all about the individual person, and ignore their social context. Jesus deliberately sought out and spent time with the marginalised, the poor, the voiceless, the excluded: the church should imitate him, and preach a gospel of social as well as personal liberation.
The primacy of orthopraxis over orthodoxy
The Church's teaching, and its attempts to formulate and systematise doctrine haven't led it to behave in a distinctively Christian way: the Church has preached Jesus Christ the liberator, but it hasn't been a force for liberation in the world. Jesus didn't preach primarily about himself or the church, but about the kingdom of God which is the total transformation of the whole world, and he acted in ways which showed that that transformation was possible here and now. When the Church emphasises orthodoxy (right belief) at the expense of orthopraxis (right action), it gets it wrong.