Ridley Scott is attached to a new film in the Alien universe, with a Jon Spaigts script, according to Variety.  The film is set to be a prequel, taking place before the first film in the series.  Scott directed that first film, with great designs by H.R. Giger creating the concepts for the aliens and its moody feel, but the three sequels were all directed by other directors (including, most famously, James Cameron on Aliens).