• Wikipedia entry on Nietzsche
• Stanford Encyclopedia entry on Nietzsche

Some of Nietzsche's thoughts

• On philosophy
• On Christianity
• On truth and knowledge
• On morality

Nietzsche studies

• Nietzsche bibliography - complete list of Nietzsche's works, plus a selection of anthologies and interpretive works
• Journal of Nietzsche Studies
• HyperNietzsche
• Nietzsche's System - online book by John Richardson, Associate Professor, Department of Philosophy, New York University