The place to start any economics literature search. Database of the American Economic Association that archives most of the major journals in economics, including the American Economic Review, Journal of Economic Perspectives, Econometrica, Journal of Public Economics and many others throughout the discipline.
The National Bureau of Economic Research is a nonprofit, nonpartisan group working to promote economics research. NBER currently features research from over 600 university professors and researchers since it was created in 1994.
Electronic depository for statistical datasets, policy reports and books published by the Organization for Economic Cooperation and Development. An excellent source for data and information on advanced industrialized countries.
Expansive database aggregating statistics from over 70 sources. Datasets have been standardized, allowing metadata and vocabulary searches. Great place to start if you are not sure who publishes the data you are looking for.