According to an interview with The Other Paper of Columbus, Ohio, John Williams will be getting to work on the score for Indiana Jones and the Kingdom of the Crystal Skull in the beginning of October. See the quotes below:
"What?s the current project you?re working on?"
"Well, I just actually put pen down on a viola concerto. And I will be doing a week for the New York Philharmonic here, and then I?ll be coming out to Columbus for one day and I?ll be looking forward to meeting the orchestra. I think they?ll be great. And then I?ll be home in California the first of October to start on the next Indiana Jones."
"Are you just going to incorporate music from the earlier movies, or are you writing any new melodies?"
"I?ll be able to tell you in about two weeks."
Click here for the full interview with such revelations as John Williams rarely going to the movies or listening to classical music.