MOS-TLY HARMLESS: You sass that Mos Def? There's a guy who knows where his towel is. Or, in other words, Mos Def is apparently onboard for the movie version of Hitch-hiker's Guide To The Galalxy, playing Ford Prefect against Martin Freeman, an excellent choice for Arthur. No word yet on who's going to take Peter Jones' role as the book, but we'd suggest Stephen Fry, oursleves. Or maybe Clement Freud.