American Presidency Project (UCSB)

Official presidential papers, 1789-1913 (Messages and Papers) and 1929 to present (Public Papers of the President)
Complete run of State of the Union and Inaugural Addresses, 1789-present
Proclamations since 1789 and Executive Orders since 1826
Roosevelt Fireside Chats, 1933-44

Indexes and lists all bill signing statements since 1929
National Party Platforms, 1840 to present (Includes third party platforms when the party received an electoral vote)
Additional materials only available to UCSB students
Also includes election results for President with voter turnout data, inaugural and State of the Union messages
Transcripts of numerous primary debates beginning 2007
Web version of Public Papers of the Presidents, 1945+ (J 80 .A25)