Pirates of Penzance Home Page: MIDI files from the opera, plus plot summary, and libretto.
The Pirates of Penzance: Brief history of the musical by Arthur Sullivan and William S. Gilbert, plus links to cast albums and sheet music.
The Pirates of Penzance: A synopsis of the musical by Gilbert and Sullivan.
The Pirates of Penzance: Learning Guide: Teachers guide to "The Pirates of Penzance" includes helpful background information and discussion questions.