Project Canterbury
A worthwhile web site including official statements of Autocephalous Orthodox Churches on the status of the Anglican Church as well as observations by the pre-Revolutionary Russian Church on the American Book of Common Prayer.
Gregorian Chant Home Page
Monumenta Musicae Byzantinae
Ecclesiastical
Calendar
Gives significant dates such as Western and Orthodox Pascha (Easter) according to both calendars, etc. Very useful when dealing with historical documents!
The Pokrov Foundation, Bulgaria