This organization is not a publisher per-se, but a project to put back
issues of key journals in various fields on-line for easy access. All
of these journals are available with a "moving wall" of 5 years (that
is, all issues from the founding of the journal to 5 years ago are
available).
In economics, the journals are
Site licenses for JSTOR are available for universities and other
organization (there are some 500 participants now around the world),
and a method for individual subscriptions is in testing.
http://www.jstor.org/