There is a lot of sites on the Web offering long lists of links pertaining to manuscript studies. In order not to copy them we recommend you just a few of them which are good to start with.
  A detailed comprehensive introduction into the topic.
  Paleography, codicology, history of manuscripts, bibliographies, plenty of links to manuscript collections and digitized manuscripts on-line.
  A list of on-line manuscript catalogues, library databases, and collections of digitized manuscripts
  A similar list of on-line manuscript catalogues, library databases, and collections of digitized manuscripts
  A huge list of various links on the topic.