Well publishing a will on a website isn't illegal once it has passed into the public domain but it will be one minuscule bat squeak in all the stuff that is published every day. If the thought brings you comfort and satisfaction then go ahead but don't expect great things. if the person who publishes it does so with the intent to defame whoever you name though then whether or not the facts are correct, they do lay themselves open to a claim for defamation.
http://www.yourrights...ents-of-a-claim.html.
I guess the only way that you could make someone actually publish your will after your death would be to make it a condition of a bequest, but it would need to be a honker of a bequest IMO