Here is a list of online resources relating to the Herculaneum Papyri. Some are in Italian or German but the essential information is usually accessible without extensive knowledge of the languages.
CISPE, the international centre for the study of Herculaneum Papyri in Naples. Includes overview of the Content of the published Volumes of Cronache Ercolanesi and La Scuola di Epicuro.
Online catalogue of Herculaneum Papyri
List of online editions of the Herculaneum texts
Papyri.info. Amalgamated catalogue of papyri worldwide including the Herculaneum Papyri with related materials. An ongoing international project.
Bibliography on the Herculaneum Papyri (Oxford Bibliographies Online). Subscription required. An earlier version covering titles up to 2006 can be found here.
Bibliography on Philodemus of Gadara (Oxford Bibliographies Online). Subscription required.
Leuven Database of Ancient Books
P.Herc. 118: images of the original papyrus roll in the Bodleian Library
Images of Herculaneum Papyri in Naples
Images of Herculaneum Papyri in Windsor Castle Library
Online catalogue of archive of the Officina dei Papiri
Published engravings of Herculaneum Papyri: Collectio Prior; Collectio Altera