From personal experience, and that of my friends, in a long distance relationship that is deteriorating, it really doesn't matter how you break the news. Idealistically, you would visit and break the news in person; however, YOU are the one that feels strongly enough that the relationship is over, so why would you put that kind of one-sided effort (effort into the relationship, so to speak) when he isn't putting enough in to keep the relationship alive? This may seem cynical, but life (and relationships, especially) doesn't always follow the rules of common decency! =) Just remember, if the relationship exists in a long distance state, and it works poorly enough that you would desire a break up, you are entitled to a long distance break up if that is what you need. I know you care for him, but the phone isn't such a bad place for doing it--just don't use e-mail! As you say, life is too short! Don't worry about these things! You should be happy that you're not so indecisive that you can't manage a break up in the first place!
Thank you for your advice on my personal situation earlier, and good luck!