Federation of American Scientists contains a treasure trove of intelligence assessments and studies useful to students interested in seeing actual intelligence products.
CIA includes the Center for the Study of Intelligence, where the CIA’s official Studies journal is available, along with many other descriptions of the intelligence process and products.
The Office of the Director of National Intelligence houses official press releases, statements, and directives; it also contains unclassified National Intelligence Estimates and other community products like the Global Trends series.
Central Intelligence Agency’s World Factbook houses the voluminous CIA World Factbook that catalogues the key facts regarding 267 world entities, including their demographics, economy, history, political structure, and other pertinent characteristics.