Just recently found this: http://diamm.nsms.ox.ac.uk/moodle/ via a link on the Resources page of DIAMM. It's a course on reading and interpreting mensural notation, concentrating on French 14th-century repertoire, but explaining principles that apply right down to the early Tudor period in England. If you previously thought that Minor Prolation was some sort of medieval torture (and having done the first module, I'm still not sure it isn't) then this is the place for you. Really - it's fascinating, fun - and free.
DF
Online course on mensural notation
Re: Online course on mensural notation
Ooh, thank you very much for posting! I am putting it on my list...