Write down the name Riley B. King. You may hear big things about this kid someday. As it is, the strapping young lad from Itta Bene, Mississippi, has been creating a buzz with his animated guitar virtuosity and amiable stage manner. King -- his friends call him B.B. -- has been heralded as a brash upstart in the blues world; the up-and-comer continues to dazzle audiences and win converts with his booming, charcoal-filtered and aged-to-perfection voice and his possessed mastery of the whistling, whining, humming guitar he calls Lucille. Lucille -- isn't that adorable? The fresh-faced youngster has yet to break into MTV's regular rotation, but it's only a matter of time. After all, he just might be the next big thing.