SPARC has released Implementing an Open Data Policy: A Primer for Research Funders.
Here's an excerpt from the announcement:
This primer addresses key issues that these organizations encounter when considering the adoption and implementation of an open data policy. The guide covers big-picture topics such as how to decide on the range of activities an open data policy should cover. It also delves into areas of very specific concern, such as options for where data can be deposited, and how privacy and other concerns can be managed.