Thanks to a reader for pointing out this site today: Cantores in Ecclesia of Portland, Oregon
"Dedicated to the preservation and promotion of Gregorian Chant and Sacred Polyphony in liturgical context within the Latin Mass of the Catholic Church"
Sounds like a worthy goal, particularly the part about "in liturgical context". While it is wonderful to hear concerts of this music, it is much better to hear it within the context for which it was written: the sacred liturgy.
Particularly of note for those in the Portland area is the Willian Byrd Festival which begins this weekend and includes an impressive lineup of Pontifical High Masses (four in total; three in the modern rite, one in the classical rite I am told), Lectures, Choral Evensong, a Chamber concert and an Organ Recital.