The California Digital Library has released "Federal Funding Agencies: Data Management and Sharing Policies."
Here's an excerpt:
The Office of Management and Budget (OMB) Circular A-110 provides the federal administrative requirements for grants and agreements with institutions of higher education, hospitals and other non-profit organizations. In 1999 Circular A-110 was revised to provide public access under some circumstances to research data through the Freedom of Information Act (FOIA).
Funding agencies have implemented the OMB requirement in various ways. The table below summarizes the data management and sharing requirements of primary US federal funding agencies.