I haven't had time yet to really look deeply into it, but I've found what looks like an interesting page for Byzantine hymnology and sacred music, called The Divine Liturgies Music Project.
The site describes itself as follows: This webpage contains more than 1000 pages of Byzantine music, transcribed into Western notation according to the style of chanting used on the Holy Mountain [of Mount Athos]. The scope of this project covers the liturgies of St. John Chrysostom, St. Basil the Great, St. James, and the Liturgy of the Presanctified Gifts, as well as various doxologies. The words of the hymns are provided in Elizabethan English, Modern English, and Greek.