Working papers in Economics are a very common scholarly communication method for Economics research. Econlit provides significant indexing of working papers, but these working paper sites can also be searched independently. Highly recommended.
Searchable index of NBER working papers. The full text of working papers from November 1994-present are available online. To obtain copies of earlier papers, see NBER's Out of Print Working Papers instructions. NBER also provides a useful set of data links on their free web site.
RePEc (Research Papers in Economics) is a large clearinghouse of Economics paper repositories. Some searching is more advanced than others depending on the functionality of the repository in question (you can also search across all the repositories). Provides citation tracking, related articles, etc. May
Full text of all Discussion Papers (working papers) from the CEPR, a European economics research network of academic research fellows and affiliates, plus abstracts for earlierDiscussion Papers, as well as the Centre's Policy Papers.
The SSRN Electronic Library, comprised of subject-based "networks," including Economics Research Network and Financial Economics Network, can be searched together or individually. Abstracts for all papers in the Electronic Library are provided, and full text is available for over half its contents. To access the full text, you will need to register with SSRN.