The Wall Street Journal reports that Cablevision Systems is close to an agreement to buy the Sundance Channel, jointly owned by NBC Universal, CBS Corp., and actor Robert Redford, in a cash and stock deal valued at close to $500 million, according to people familiar with the negotiations. A purchase of Sundance will strengthen Cablevision's position in the independent-film programming arena as the cable operator already owns another film channel, IFC. Terms of the deal may be announced as early as Wednesday morning. The deal could be the first of two half-billion dollar purchases for Cablevision, based in Bethpage, N.Y. The cable operator has also made a bid of as much as $650 million for Long Island newspaper Newsday.