These last few years I've given a lot of thought to what happens to what I've made after I've passed on. Typical for someone at my stage in life, but also a typical response to losing one's friends and family members as one begins to do. For a long time I worried about my legacy - what it would be, if I even have anything that could be considered such. But in time I came to understand that it is what I do now that matters - being a good steward to the gifts and talents I've been given.
Still, there are folks -- artists, writers, musicians . . . all the makers -- who have lots of actual stuff they've made. It matters, not simply as a legacy, though it might be that, but as a memory, a memorial to their talents and dreams. It is also a matter of providing for one's heirs - telling them how to handle the intellectual property issues associated with the stuff you've created.
Author Neil Gaiman posted some useful info to his blog a while back on how to do this. And he provides a working document for those who need one. Here's his link. It includes the PDF file for the document he refers to.