Thanks to NLM reader Juan for sending in this link: Gregorian Chant
Apparently this site has all the chants of the Sundays through the year, as well as solemnities, with a provisory Tridentine concordance.
This could be a useful tool for those singing Gregorian chant propers, as well as the ordinary if they wish to hear what the chants sound like.
For those that want a more permanent, hardcopy form of this, some have recently pointed me to the following:
40-CD set available through Angelus Press
The CDs have the Propers for all the Sundays of the year and most important feasts of the Temporale.
There are also individual CDs (info on request) for a number of other feast days.