Inter-University Consortium for Political and Social Research http://www.icpsr.umich.edu/ The Consortium says it's "the world's largest archive of digital social science data. We acquire, preserve, and distribute original research data and provide training in its analysis." The data files are searchable and browsable; each item retrieved includes a description, scope of the study, dates and geographic region, methodology, and information on access. There's a data use tutorial on the website as well. -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.