A man finds out he is really a character in a book and the author plans to have him murdered in th final chapter. What is the movie?

Are you thinking of "The Number 23?" I haven't seen it in a long time, but if I remember right, that is what the plot of it was. Jim Carrey was the main character. I hope I helped you! :P

Stranger Than Fiction (http://www.imdb.com/title/tt0420223/)