Weber's theory of social classSocial inequality and classes
Many links to classes, poverty, stratification and inequalities.Social class and stratification
Links to Veblen, Marx, etc.Social StratificationPoverty Reduction and Equity
From the World Bank. Covers surveys, publications and data.Poverty
From the US Census Bureau.Explorations in Social Inequality
There are many sites here, some of which are biased and opinionated.