The most useful web links can be found on the Gregorian Chant Home Page

Gregorian Institute of Canada

The Gregorian Association (London, England) presents an introduction to the practice of Gregorian Chant

The website of Luca Ricossa contains useful documents on Plain-Chant

The official web site of the Abbaye St-Pierre de Solesme (France) contains, among others, a brief history of Gregorian chant, capsule definitions of various types of Gregorian compositions, as well as the list of publications of the Éditions de Solesmes.

Abbaye St-Benoît-du-Lac (Canada)

Abbaye de St-Wandrille (France)

Choeur grégorien de Paris

Grimbergen Abbey Gregorian Choir (Belgium)

International Gregorian Chant Festival of Watou (Belgium)

Les Journées du Chant grégorien à l'abbaye de Clervaux (Luxemburg)

The website Order of Saint Benedict yields a great number of interesting links on Gregorian Chant

Société québécoise de recherche en musique (SQRM)