The NIH requires that a manuscripts resulting from NIH funding be deposited in PubMed Central in the final peer-reviewed form within 12 months of publication. The specifics of this requirement can be found at the NIH Public Access Policy Overview website. For more resources to help you comply with this requirements, please visit the our EHSL NIH Public Access guide. Articles can be submitted to PubMed Central through the NIH Public Manuscript Submission (NIHMS) system. Some publishers restrict what can be done with articles published in their journals, SHERPA-RoMEO has a list of Publisher Policies on copyright and self-archiving.
The Federal Research Public Access Act is a bill that would attach public access policies, similar to the NIH Public Access Policy, to all research conducted using federal funds.
From the Association of Research Libraries' SPARC summary:
"FRPAA would require that 11 U.S. government agencies with annual extramural research expenditures over $100 million make manuscripts of journal articles stemming from research funded by that agency publicly available via the Internet. The manuscripts will be maintained and preserved in a digital archive maintained by the agency or in another suitable repository that permits free public access, interoperability, and long-term preservation. Each manuscript will be freely available to users without charge within six months after it has been published in a peer-reviewed journal."
More information from the Alliance for Taxpayer Access
Since January 1, 2008, the Howard Hughes Medical Institute has required that its scientists publish their articles in journals that allow for the article to be made freely accessible in public repository within six months of publication. PubMed Central is the designated repository for biological articles. Articles in other disciplines should choose a comparable repository.
For more information see the HHMI Announcement, the Public Access Publishing section of the HHMI Research policies page, the full text of the official policy, and an HHMI resources page for assistance in complying with this policy.
The Wellcome Trust requires that peer-reviewed research papers be deposited in PubMed Central and UK PubMed Central within six months the journal's official publication date and will provide funding to cover open access fees.
For more information, see the Wellcome Trust policy statement. Additional resources can be found on the Wellcome Trust Open Access page.
Autism Speaks requires that the final peer-reviewed manuscript of articles supported by Autism Speaks funding be deposited in PubMed Central, to be made publically available within 12 months of publication.