The Wagner Journal
London-based journal edited by Barry Millington, with thought-provoking articles written by an eclectic group of scholars and artists. This is a highly recommended resource for the latest ideas in Wagner interpretation, along with reviews of books, performances and more. Online subscriptions also available.
New German-language journal devoted to Wagner research. Founded in 2005 by Udo Bermbach, Dieter Borchmeyer, Hans Vaget, and others, the editorial board is a who’s who of Wagner scholars worldwide. Each issue focuses on one specific theme or question, but also contains free-standing articles and reviews.
Wagner in der Diskussion
New series of books published by Königshausen & Neumann (publishers also of WagnerSpectrum).
Wagner’s Prose Works in English Translation
Complete online edition of the William Ashton Ellis translation
Stanford University Opera Project
Includes lots of useful information/performance data on Wagner's works, including libretti in German.
Extremely informative site run by Per-Erik Skramstad in Norway. Emphasis is on the stage works and their performance. Includes reviews of recent books and recordings.
Richard Wagner Archive
Site designed and run by Hannu Salmi, Professor of Cultural History at the University of Turku, Finland.
Note: The Wikipedia sites devoted to Richard Wagner and his individual works are generally good and dependable.