Do you need a TV? Not really. After all, at Syfy you can watch “Battlestar Galactica,” “Sanctuary,” and “Destination Truth” right on your computer. Trekkers, Leapers, and X-Philes unite! The website beckons you with a virtual Vulcan archive of science fiction materials of every sort. Aside from the requisite program guides and online episdoes, you’ll find video clips and sound bites from classic science-fiction TV shows and films, along with forums, and an astonishing array of articles, interviews, and reviews. Whether you’re into “Lord of the Rings” or the latest from John Carpenter, sci-fi fans can’t go wrong by spending some time perusing Syfy.