I found an excellent blog post by Neil Gaiman about the special importance for writers to have a will with a link to a sample will that covers intellectual property.
http://journal.neilgaiman.com/2006/10/important-and-pass-it-on.html My parents died without a will and I spent most of what little money was left after funeral expenses on legal expenses getting the mess sorted out and they were working people with a small patch of land and no investments.
I'm guilty of this myself because I just do not have the money to pay a lawyer right now, mostly because of the cost of dealing with their estate, but I urge anyone who can cough up a spare couple of hundred to insure their family doesn't have to go through additional hell after you die to do it. Make it your New Year's resolution.