A symposium:
http://www.aasianst.org/EAA/Siddhartha.htm
discussing Siddhartha's faithfulness to the Indian religious ideas it invokes.
The official web site:
of the Hermann Hesse museum in his home town of Calw, Germany. It provides a biography, list of works, and a virtual tour of Calw.
A virtual clearinghouse of information on Hesse:
http://www.ic.ucsb.edu/~ggotts/hesse/
this site provides links to biographies, e-texts, secondary literature, etc.
This site:
http://www.levity.com/corduroy/hesse.htm
includes newsgroups, quotes, articles, essays, and reviews related to Hesse and his works.
A short, but interesting analysis
http://www.gss.ucsb.edu/projects/hesse/works/sidd.html
of Siddhartha along with information about various movie adaptations.