Pew Research Center
National surveys of individuals' values and beliefs in more than 80 societies.
PIPA (Program on International Policy Attitudes)
Studies public opinion on international issues "...with the purpose of giving public opinion a greater voice in international relations." 1994-2001 publications available and post-2001 at WorldPublicOpinion.org.
European Commission, Public Opinion Analysis sector.
Produces a biannual study comparing American and international public opinion.
Guide to mostly free sources from Princeton Libraries; includes election studies.
A research network based out of U Michigan that has been conducting opinion surveys in the MENA countries since 2006. It is the largest repository of publicly available data on views of men and women in the region. They also have a data analysis tool where you can download the results.
Odum Institute (1960- )
Contains the National Network of State Polls and is maintained by the University of North Carolina. Largest collection of state level polls.
National Journal polling data on political events of the day.
Pollingreport.com (1985- )
Summary-level highlights from recent national polls.