This resource is a fantastic archive for all things Presidential. The American Presidency Project from the University of California-Santa Barbara contains over 86,000 documents, including proclamations, executive orders, debates and convention speeches. There is a large variety of statistics, for example approval ratings, election results, vetoes and public appearances. There is also an audio/video archive going back as far as President Hoover.
It would be hard to find so much Presidential information and history collated so well into one site anywhere else. Have a browse!