The Aberdeen Bestiary Project -- background info and images of medieval manuscript illuminations.
MRDS: The Medieval and Renaissance Drama Society -- Mailing lists, journals, organizations and societies involved with medieval drama.
The Keepers of Knowledge -- How knowledge and learning survived in the middle ages.
Medieval Music of Cyprus -- Historical background of medieval Cyprus and the flourishing musical culture of the 13th through 15th centuries.
Who in Medieval Literature -- 28 Writers, Dramatists & Poets
listed by the About.com website.