Linda Paterson (author of The World of the Troubadours and many other scholarly publications on troubadour-era literature and culture) and a team of colleagues have put a number of Crusade lyrics online:
http://www2.warwick.ac.uk/fac/arts/modernlanguages/research/french/crusades/texts/occitan/
I don't know about you, but I plan to make exensive use of this corpus for my own works in the near future.