The November 2003 World Health Organization Millennium Development Goals paper states: "(N)early all of this year's 10.8 million child deaths will be confined to the world's 42 lowest-income countries, concentrated in sub-Saharan Africa and South Asia. Diarrhoea, pneumonia, and neonatal conditions are the most important causes of childhood mortality worldwide, with malaria and HIV infections contributing in many areas. Malnutrition is associated with 54% of all child deaths."
As for some specific statistics, the UNICEF report The State of the World's Children 2004 shows the following: