Harold Varmus, former NIH director and instigator of open-access publishing, writes a personal account (PDF file) of his conversion to open-access, and the events leading to the founding of PubMed Central and Public Library of Science (PLoS).
The paper was originally presented at a symposium in 2007 organized by the American Philosophical Society.
He rightfully points out the basic facts behind this issue: most scientific research is paid for by public funds, and scientists themselves contribute their time and energy to peer-review and edit articles for scientific journals as part of their service to the scientific community (and to build up their own resumes).
However, for-profit companies (and some non-profit societies) that publish these journals charge subscribers high rates (often several thousands a year for institutional subscriptions) and enjoy large profit margins. In an (probably) unintended confluence with other current events, he quotes a report from the now-defunct investment firm Bear Stearns that calls the European publishing conglomerate Reed-Elsevier "a stockholder's dream come true."
Being then the director of the NIH, which funds most biomedical research in the US, he came to the realization that his agency was inadvertently subsidizing the publishing industry to the tune of perhaps 1 billion dollars a year.
One may or may not agree with the PLoS model of open-access, where authors of scientific articles have to cough up publication fees (of a few thousand dollars) to make their work freely available to the public. His essay is however still good reading for anyone interested in a spirited insider's look into the politics and economics of science.