Open Access to Academic Journals?

There was a conference at Southampton University in England this past week on providing open access to scholarly information over the internet.

Though I'm strongly in favor of open access, I don't know how this model would work. Scholarly journals make most of their money from institutional subscriptions, which only make sense if material is not easily available for free to anyone.

What is being suggested at Southampton is a model where scholars archive their published works on their university servers. The universities, not the journals, provide the open content. But why would the journals allow or encourage this? Don't they have the publication rights? Or maybe I just don't understand what is being proposed.

That said, according to the article in the Guardian, most publishers in Europe at least are in favor of allowing open access for materials that are self-archived.