This TED talk from Stanford's Daphne Koller does a great job describing the process and benefits (and limitations) of this new frontier in education.
Access to education is an important sustainability issue:
First, there are all of the basic benefits we think of regarding a better educated population -- more thoughtful and skilled people, being more productive and supporting better quality of life for all, etc.
Second, education is an effective satisfier of basic human needs - primarily that of understanding, but also indirectly of participation, subsistence, identity, and protection.
Finally, education is necessary for people to understand enough about the social and ecological dynamics of 'un-sustainability' -- how we got to the place we are, how the global economic system cumulatively affects social and natural systems, how the basics of biogeochemical cycles work, etc. -- to be able to create a sustainable society.