Daremberg-Saglio
A PDF-version of the Dictionnaire des antiquités grecques et romaines has been put online by the Université de Toulouse.
De Ruggiero
An online version of De Ruggiero’s Dizionario epigrafico di antichità Romane
A-B: http://archive.org/details/dizionarioepigr00rugggoog.
C: http://archive.org/stream/dizionarioepigr01rugggoog#page/n7/mode/2up
Pauly Wissowa
Several digitalised version of this Mother of all Encyclopaedia’s circulate on line:
http://de.wikisource.org/wiki/Paulys_Realencyclopädie_der_classischen_Altertumswissenschaft
http://archive.org/search.php?query=Pauly-Wissowa%20AND%20mediatype%3Atexts