A couple of weeks ago Dave Thompson at the Wellcome mentioned to me that he had been interviewed by the BBC's world service on the subject of digital wills - see a post on the subject on Wellcome's blog. I also stumbled on some interesting references relating to digital estate planning via the Law Professors Blog Network, which includes a blog dedicated to wills, trusts and estates.
Many of us have digital materials online (or offline) that we want to pass on to friends and family. By outlining where materials are and supplying account credentials, we can ensure this happens. It could be done in regular estate planning, or simply keeping a note somewhere safe (and telling the right person where to find it!). There are also online services springing up to help people make arrangements for passing on the relevant information. Research libraries have an obvious interest here; digital material is an important part of a person's archive, and unless someone knows it exists, where to find it, and how to access it there is little prospect of saving it for future generations.