Here's a quick heads-up for fans of great American TV. Tonight is the premiere of THE US telly phenomenon of the year when BBC2 shows the first two episodes of Heroes. Now it may look like a geeky sci-fi show about superheroes and, yes, in some ways it is a bit geeky, but it's also completely addictive, brilliantly smart and full of attractive, sexy young things. Who happen to have superpowers. And unlike Lost, which frankly lost a lot of us with its reliance on a five-year, slowly unravelling plot, Heroes resolves its mysteries in far swifter fashion so we promise you won't get too frustrated. So tune in to BBC2 tonight at 9pm (or set your personal video recording devices while you watch BB), or even better if you have High-Def TV, the BBC's HD channel (143 on Sky Digital) is showing it in stunning high definition. If you don't have HD, just imagine everything looking twice as sharp...