Internet History Sourcebooks Project
Fordham University: Medieval Sourcebook: Einhard: The Life of Charlemagne
Has the complete text of the Life of Charlemagne, which is the only first person account on Charlemagne available to historians. Contains 33 chapters which includes every detail of Charlemagne's life that you could possibly imagine.
Steven Kreis, PhD
The History Guide: Charlemagne, 742 814
Brief biography with links to further biographies and Einhard's "Life of Charlemagne."
Robin Chew
Lucidcafe: Charlemagne
Gives a short account on the life of Charlemagne plus has links to other sources of information.