Kim C:

The Dufay Collective: "A Dance In The Garden of Mirth" "Miri It Is" Chandos Records

New York Ensemble for Early Music: "Istanpitta" "Istanpitta II" Lyrichord Discs

Also check out the following web-sites; Harmonia Mundi in particular carries a great many early music recordings:

http://www.medieval.org/emfaq/misc/labels.htm

http://www.wu-wien.ac.at/earlym-l/

http://www.concerto.demon.co.uk/category.html

Enjoy!