Gile na Gile, what a good idea, I have used the sites that you have posted, fordam and celt are excellent resources, I have whiled away many an hour browsing these sites both for study and leisure. With Project Guttenburg many of the classics are at hand as you say, plus out of print and more obscure literature, all of which can give a particular ‘feel’ to a period of history under study.
May I contribute;
A rather good site for anyone with an interest in the ancient near east.
ETANA (Electronic Tools and Ancient Eastern Archives) http://www.etana.org/
And its sister search site;
Abzu is a guide to networked open access data relevant to the study and public presentation of the Ancient Near East and the Ancient Mediterranean world. http://www.etana.org/abzu/
For a plethora of web sites try Intute, http://www.intute.ac.uk/about.html
Intute is a free online service providing access to the very best web resources for education and research. All material is evaluated and selected by a network of subject specialists to create the Intute database.
For the Arts and Humanities http://www.intute.ac.uk/artsandhumanities
Hope these may be of help to someone