Online repertories and corpora (general):
Corpora and collections of Greek inscriptions (general)
Corpora and repertoria Athens and Attica
Corpora and repertoria Greece & Islands
Online corpora and repertoria Asia Minor
Online corpora and repertoria Other regions (Greek)
Online edition CIL (Arachne)
Se also here for a linlk to the CIL site at the Berlin-Brandenburg Academy (with links to Arachne)
See also: Archivum Corporis Electronicum for access to the collection of squeezes photographs etc.
For an online version of Dessau ILS on archive.org click here