For those interested in the music of Heinrich Isaac, as well as its celebration both in concert and in the context of the Mass, and especially for those who happen to be in or near Budapest, you might want to check out the following links:
Choralis Constantinus 500 is a Hungarian project to sing through the entirety of the Choralis Constantinus of Isaac. The site includes multilingual booklets of the pieces sung at the concerts & Masses, as well as handouts of the chant which is sung altenatim with the polyphony. The project began on November 30, 2008, and it is scheduled to be completed on November 22, 2011. The site itself is in Hungarian, German, and English. They have a Facebook page as well.
If your Hungarian isn't too rusty, check out Capitulum Laicorum Sancti Michaelis Archangeli who are involved in this very worthy project.
God bless Hungary, Shield of Christendom!