In 2008 the Chongqing government installed a 'Migrant Worker's Day' to recognize the contribution of migrant workers to the building of the area. The People's Daily reports that three migrant workers have made it to the top. For what it is worth - 3 people out of millions is not much - these things show the concern of the government.
What is maybe more important is the solidarity between people. Wei Wei, himself a migrant worker, is one of the people who engages in the rights of migrant workers. A few years ago he established an organization Xiao Xiao Niao, meaning 'little bird' to help migrants to overcome there difficulties. They take action is case of non-payment, maltreatment or abuse. Contract conditions of migrant workers are studied by several organizations like for instance SACOM (students and scholars against corporate misbehavior).
Many films are made about the difficult situations of migrant workers in China. Two I like very much are Guo Xiaolu's 'The Concrete Revolution' telling the story of changing China, and David Redmon's 'Mardi Gras. Made in China' contrasting the production of beads in China with the consumation of these beads in the USA at the carnival festival. A shocking eye-opener this last one is as it strongly shows the ignorance of a consumer society.