Afrobarometers--The Afrobarometers are an ongoing series of surveys conducted amongst countries in sub-Saharan Africa, focusing on topics such as civil society, government, and state-society relations. The Electronic Data Center has most of the Afrobarometers available here.
American National Election Studies (ANES)--The ANES series is one of the premier sources for data on voting behavior and political attitudes in the post-WWII United States. Upon registering (which is free), users can download data and SAS/SPSS/Stata program files and documentation for any of the various ANES studies. The SDA Archive at UC-Berkeley also allows users to access recent versions of the ANES and extract particular variables from them for those who have specific questions in which they are interested.
Association of Religion Data Archives (ARDA)--The ARDA is an excellent site for numerous surveys on issues of religion. There are many downloadable datasets and codebooks. Researchers should go to the "Data Archive" for a directory of the different studies available.
International Index of Public Opinion--A consortium of polling agencies compiles this yearbook every year. It contains questions on a large number of topics from opinion polls and surveys across a large number of countries. Unfortunately, this reference is not available online. However, it is available in Woodruff Reference (HM261. I5532).
JARS (U.S. Officials Job Approval Ratings)--The U.S. Officials Job Approval Ratings page is run by Thad Beyle at UNC-Chapel Hill and contains a wealth of time-series data on job approval ratings for U.S. presidents, senators, and state governors.
Latinobarómetro Data--The Latinobarómetro is an annual survey conducted amongst 18 countries in Latin America. The survey, which has been conducted since 1995, asks respondents about topics such as globalization, democratic governance and political institutions, "social capital," the environment, and gender issues. The Data Center has microdata files for this survey from 1995 onwards.
Pew Research Center for the People and the Press--The Pew Research Center for the People and the Press is a major center for the study of public opinion and regularly conducts polls (both at home and abroad) about various social and political topics and contemporary issues. They make many of their studies available for download here. Many of the more recent datafiles are in SPSS format. Users are required to register before downloading a dataset, but registration is free. Users should also check out the resources available via the Pew Research Center homepage.
Polling the Nations--This website allows you to search a large database of surveys and opinion polls primarily in the United States, but also in European Union countries as well as in several other countries.
The Roper Center--The Roper Center is one of premier polling-data archives in the country. Its holdings cover a wide range of topics. The iPOLL search page may be of particular use because it allows users to search at the question level. Roper is also accessible via Databases at Emory.