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.