Here is a web site that may be of interest: Electronic Text Center / University of Virginia Library:
<<etext.lib.virginia.edu>> (no www.).
A link takes you to Fitzpatrick's Writings of George Washington for digitalized transcriptions you can download and manipulate. As far as I can determine, all the documents in the published volumes are available, and the navigator is simpler to use than the one in George Washington Papers at the Library of Congress (but you are still obliged to consult the latter site if you want to look at the manuscripts).
To Join the Company of Military Historians click here