FASB is best known as an organization that creates the accounting standards that guide the practices of accountants and auditors in the U.S.. The FASB web site includes information on the Board, its activities and publications.
As of July 1, 2009, the only authoritative source for FASB standards is the FASB Accounting Standards Codification (FASB Codification). The Codification is available online. You can register for either free "Basic View" access or subscribe to get advanced features. Once you have registered, you login with your username and password.
FASB formerly published many types of materials including Statements of Financial Accounting Standards (SFAS), Statements of Financial Accounting Concepts (SFACs), Interpretations, Technical Bulletins, Exposure Drafts, Discussion Memorandums, Invitations to Comment, Research Reports, Special Reports and a newsletter called Status Report.
Pre-Codification materials where generally published first as individual paperback volumes or pamphlets and then republished in a multi-volume looseleaf service called Original Pronouncements and a CD-ROM called the Financial Accounting Research System (FARS). You may be able to find these historical materials in business school libraries and other libraries that collected accounting materials. Some pre-Codification FASB materials -- Statements of Financial Accounting Standards, Statements of Financial Accounting Concepts, FASB Interpretations, FASB Staff Positions, FASB Technical Bulletins and EITF Abstracts -- are posted on FASB's Legacy Standards page.
FASB materials are also available through CCH's Accounting Research Manager and RIA Checkpoint. Some FASB materials may be available in the AICPA's subscription-only "reSOURCE online" database on CPA2Biz.com.
Pre-1995 FASB materials may be still available on Lexis and/or Westlaw.