There are three kinds of Congressional Resolutions: Joint, Concurrent, and Simple (also called "House Resolutions" or "Senate Resolutions").
Simple Resolutions (a/k/a House or Senate Resolutions) are published in the Congressional Record (see the Congressional Record entry for print and online sources). Recent Simple Resolutions are posted in the Congressional Bills section of FDsys from the 93rd Congress (1973-1974) to the present. They are also posted on Thomas, mixed in with the Bills, from the 104th Congress, 1994-1995 to the present.
Joint and Concurrent Resolutions are published officially in Statutes at Large, though after a considerable time lag. Recent ones are available
on in the Congressional Bills section of FDsys from the 103rd Congress (1992-1993) to the present. They are also published in CIS's Bills, Resolutions and Laws (1833-2008) microfiche after the end of each Congressional section. The CIS microfilm is available in some academic libraries, or you can buy individual Resolutions by calling ProQuest (800-638-8380) with the title, date and CIS accession number (you can look up the accession number in the CIS Index to Congressional Publications and Public Laws). Order forms and instructions are available; don't worry if the documentation does not yet reflect CIS' transfer from LexisNexis to ProQuest.
Legislative Histories compiled by the GAO for selected Public Resolutions enacted from 1915 to 1995 are included in Westlaw's FED-LH database.