Below are some useful links to medieval studies sites. It should be noted that this is a supplement to the list of further reading, not a replacement for it.
Encyclopedia of the Middle Ages
A reliable scholarly encyclopedia with articles by named specialists. The encyclopedia is still in development but offers good information on some major historical figures and key concepts. Much safer than Wikipedia!
A useful starting point for looking for medieval studies resources on the Web
A searchable database of articles and other critical material relating to the study of medieval women and gender
British Library Resource giving basic, but reliable information on medieval society and culture