The biggest gamble in the short life of satellite radio hits the table at 6 a.m. today, as Howard Stern starts what he calls his creative rebirth at Sirius. The most prominent morning host on commercial radio for 20 years, Stern joined Sirius because he says the FCC's vague content guidelines made it impossible for him to do his "real show" any more. Because satellite listeners pay a monthly subscription fee, like cable TV watchers, the FCC does not regulate content - though Stern's arrival has amplified calls for such regulation to be authorized. Stern's switch to Sirius, with his...