Alexandria Digital Library
Based out of  UC-Santa Barbara, this library collects geographical material

Documenting the American South
As part of the University of North Carolina Library system, this is a collection of  text, images and sound about the South. 

California Digital Library
An entirely digital member of the University of California library system, with access to scholarly resources. 

Perseus Digital Library
Collections of digitized materials that are searchable and crossreferenced. 

Digital Library Federation
A group of libraries that are providing digital library services

JCDL
The Joint Conference on Digital Libraries information page. Contains the proceedings from a number of conferences.

D-Lib magazine Web magazine about digital libraries

Ariadne magazine British digital library magazine