If you're a fan of HBO's Boardwalk Empire, you'll probably want to tune in to PBS' new Prohibition-era doc -- on your iOS device. That's right, the federally-funded public station's hip to our digital distributing times, and is giving an early access viewing window to users of its PBS app across Apple's iPad, iPhone and iPod Touch. The high-brow art'll get its stream on September 23rd, with the full series to air on broadcast from October 2nd through the 4th. While the doc's two subsequent episodes will also stream live day and date on