Eurobarometers
http://ec.europa.eu/public_opinion/index_en.htm
The European Union has been conducting the Eurobarometer series amongst the publics of EU member-states since the early 1970's. They provide a dynamic measure of European attitudes toward economic, political, and social attitudes within the European Union. The European Commission provides access to a wide variety of reports produced from the Eurobarometer series of studies. The primary data archive for the Eurobarometer series is the German Social Science Infrastructure Services (GESIS). GESIS also has a search engine for Eurobarometer codebooks and questionnaires that is very useful for identifying the topical contents of individual studies. Microdata for many Eurobarometers are also available from the ICPSR. The Data Center also has an extensive collection of Eurobarometers, including studies conducted in Central and Eastern European countries.
International Social Survey Programme (ISSP)
http://www.issp.org/
The ISSP is an ongoing effort devoted to cross-national research on social attitudes. In addition to asking general questions about attitudes towards various social issues, the ISSP series also includes special topic modules focusing on matters such as national idenitity, the role of government, social equality, and gender roles. The primary data archive for the ISSP is the German Social Science Infrastructure Services (GESIS). GESIS also has a search engine for ISSP codebooks and questionnaires that is very useful for identifying the topical contents of individual studies. The Data Center also has many ISSP data files available here.
World Values Survey Series
http://www.worldvaluessurvey.org/
The World Values Survey is "a worldwide investigation of sociocultural and political change. It is conducted by a network of social scientist at leading universities all around world. The survey is performed on nationally representative samples in almost 80 societies on all six inhabited continents." It is an excellent source for cross-national survey data and is a widely-referenced resource. The Data Center has data from four "waves" of the World Values Survey available here.