Monastery of Saint Peter of Solesmes, France (in english and in french). Solesmes is known, among other things, as a big center of studies and diffusion of the gregorian chant. In this site there are informations about available gregorian chant books and CDs.
To read these chants from the scores, this site about the "square notation" (after the shape of the notes) is a good help, including a comparison with the modern pentagram. But before the first scores appeared there were other forms of notation, used to help the cantores (trained singers) - as the chants went known by heart along the years - as can be seen in the "Plainchant Homepage" site from Willy Schuyesmans (look for "the music" and then "the neumes"). In this beautiful site you can find a brief gregorian chant history, and many other interesting informations. The relatively recent spread interest in these ancient notations, called paleographic, is due mainly to the discoveries of Dom Eugène Cardine, osb; the study of those notations (semiology) allows the singing of gregorian chant as in its origins, because they bring us many nuances and subtleties lost with the square notation... If we know a brief history of Gregorian Chant, and also a little about antique religious orders, it's not strange that chants besides the "authentic" gregorian appeared; this is explained in the "Norbertine Gregorian Chant" page, which summarizes the history of those chants (gregorian and norbertine), its liturgical value and chant restoration based in the study of the neumes. Richard Lee has a page plenty of gregorian links, it deserves a visit if you want more information. Also with many interesting links is the page from Peter Jeffery, "The Gregorian Chant Home Page", problably one of the first pages devoted to chant in the net.
A brief tutorial about chant is available at Dan´s site, including some practices (the theories about rithm and chironomy) previous to more recent semiologic discoveries.
Who wants to know more about liturgy, be it the one from
Saint
Pius V (Tridentine) or from Pope Paul VI ("Novus Ordo"),
there is information in the site "The
Catholic Liturgical Library", where I found a very interesting
commentary
on the participation
of the faithful in the Mass - what includes singing when
appropriate.
Beware, though, if you are interested in the Tridentine Mass,
because
some supporters of this Mass and respective traditions, when they are
connected
to the "Society of Saint Pius X" (SSPX
or, in French, Fraternité Sacerdotale Saint Pie X , FSSPX), followers
of Mons.
Lefebvre, are schismatic! See the letter Ecclesia
Dei and additional
information about the Pontifical Commission in the official Vatican
site. I´m glad to say that, since the 18th January of 2002, a
group
here in Brazil, from Campos in Rio de Janeiro, which was close to the
SSPX,
returned to the Church - after 20 years of schism; however some chapels
and minor groups remain schismatic in this country. You can look for
the Priestly Fraternity of Saint Peter (FSSP, Fraternitas Sacerdotalis Sancti
Petri) without any fear, because they are not schismatic, they are in
full communion with Rome and the Church.
Some chants from this site are used (or linked to) in interesting
sites around the world. One of them, "The Middle Ages Online", has
a short page
devoted to the music (http://www.themiddleages.net/life/music.html)
from those ages.
update: 29/3/2005 (previous 3/2/2005)