United Nations - Child Labour - gives overview, vital statistics, short video, and links to policies, and other resources.
International Programme on the Elimination of Child Labour (IPEC) - part of the International Labour Organisation - IPEC had statistics, publications, overviews on child labor.
International Statistical Agencies links to specific countries. Here the researcher will find statistics concerning children and health, labor, demographic information, etc.
Human Rights Watch has an important report of child labor in the US in the tobacco fields