The most complete collection of online resources for Medieval Philosophy has been compiled by Jean-Luc Solére for the S.I.E.P.M.:
http://capricorn.bc.edu/siepm/
Here is an overview of the types of resources to be found there:
News and notes for the medieval philosophy community
Overview of journal publications in medieval philosophy
Bibliographies and encyclopedias
Editions of text (ebooks and digitized books)
Dictionaries, concordances, indices, language learning tools
General information, research centers, projects, and learned societies
SMRP 