Google Book Search - By default the link I've provided searchs for and provides full text 19th century documents (all free).  If you are interested in history and you have some key words you want to search for this is an outstanding resource.

Audio Books - This website offers free, downloadable audio books.  Just enter the authors name or book title in the search.

Primary Source Documents Pertaining to Early American History

The Online Library of Liberty

Teaching American History

The Constitutional Convention - Daily Time Line Summary with Links to Text

http://www.gutenberg.org/ - Free Ebooks

http://www.fullbooks.com/ - Free Ebooks

http://www.usconstitution.net/

http://www.law.cornell.edu/constitution/overview

http://www.lonang.com/exlibris/library.htm - Writings in natural law

http://www.historycarper.com/resources/

http://www.founding.com/founders_library/pageid.2118/default.asp

http://avalon.law.yale.edu/default.asp

http://www.nlnrac.org/archive/topic_and_subtopic - Natural Law, Natural Rights and American Constitutionalism. Classical to Modern

http://millercenter.org/president

http://public.wsu.edu/~amerstu/19th/hist.html

http://www.archive.org/details/texts

http://www.thefederalistpapers.org/

http://press-pubs.uchicago.edu/founders/

http://memory.loc.gov/ammem/index.html - Library of Congress

http://www.fed-soc.org/ - The Federalist Society for Law and Public Policy Studies

http://www.revolutionary-war-and-beyond.com/index.html

http://www.archives.upenn.edu/index.html

http://constitutionalawareness.org/

http://deila.dickinson.edu/theirownwords/

http://www.hathitrust.org/

http://www.1828-dictionary.com/ - The earliest usable dictionary I have been able to find online.

http://www.forgottenfounders.org/

http://www.literaturepage.com/

http://colonialhall.com/index_t1.php

http://www.bucklinsociety.net/

http://www.google.com.au/ - Yes, Google. You will be amazed at what you can find by using Google, Australia that you can't locate using Google.us

http://www.quia.com/pages/constitutionalstudies/scholars

http://www.loc.gov/rr/news/oltitles.html - Newspaper Archives/Indexes - U.S./International

 http://www.timepage.org/spl/13colony.html - The history of the original 13 colonies (in brief) up to ratification of the USC. Constitutions' of the original 13 States.

http://www.fordham.edu/halsall/mod/modsbook12.asp 

http://www.earlyamerica.com/

Foundational Documents

(1774-1789) Journals of the Continental Congress - Letters of Delegates - Elliot's Debates  -Farrand's Records

(1776) Virginia Declaration of Rights (Audio Version)

(1777) The Articles of Confederation - Agreed to by Congress November 15, 1777; ratified and in force, March 1, 1781

(1781) Jeffersons Notes on the State of Virginia

(1787) Notes of the Secret Debates of the Federal Convention

(1787) The Records of the Federal Convention of 1787, 3vols. - The Farrand editon is considered to be the most complete.

(1788) Constitution of the United States - Original Constitution. The best E-version I have found. All changes to the original are in hyper-text taking you to the Amendment that altered it.