Some sources to learn more about the Open Access movement in general:
SPARC Open Access
Scholarly Publishing and Academic Resources Coalition (SPARC)'s page and resources on Open Access
UNESCO Global Open Access Portal
Presents a snapshot of the global Open Access movement, focusing on the member states of the United Nations Educational, Scientific and Cultural Organization (UNESCO)
Simmons Open Access Directory
A wiki that collects topics common to Open Access publishing, and information about them
Transforming Scholarly Publishing Through Open Access: A Bibliography
A 2010 bibliography of sources about various topics in Open Access
Open Access Videos
Videos about Open Access, from the Open Access Week website