JISC has released a guide to including research data in repositories: Policy-making for Research Data in Repositories: A Guide.

Here is an excerpt from the introduction:

The Policy-making for Research Data in Repositories: A Guide is intended to be used as a decision-making and planning tool for institutions with digital repositories in existence or in development that are considering
adding research data to their digital collections.

The guide is a public deliverable of the JISC-funded DISC-UK DataShare project (2007-2009), http://www.disc-uk.org/datashare.html, which established institutional data repositories and related services at the partner institutions: the Universities of Edinburgh, Oxford and Southampton. It is a distilled result of the experience of the partners, together with Digital Life Cycle Research & Consulting. The guide is one way of sharing our experience with the wider community, as more institutions expand their digital repository services into the realm of research data to meet the demands of researchers who are themselves facing increasing requirements of funders to make their data available for continuing access.