The Mozart Projec t New this month: reviews of two easy-to-use guides to Mozart's music. They are A Listener's Guide to Mozart's Music and The Mozart Starter. Both are brief and personal, a perfect way to introduce yourself (or a friend) to the music of this composer. Upcoming: reviews of Robert Gutman's long-awaited Mozart: A Cultural Biography, just published, and Ruth Halliwell's The Mozart Family, out last year.