Ridley Scott has been talking to MTV about the forthcoming Alien Prequel. It will be set 30 years before the original. Scott said “It's set in 2085, about 30 years before Sigourney [Weaver's character Ellen Ripley]”
Scott also said "It's fundamentally about going out to find out 'Who the hell was that Space Jockey?' The guy who was sitting in the chair in the alien vehicle — there was a giant fellow sitting in a seat on what looked to be either a piece of technology or an astronomer's chair. Remember that?"
As well as the space jockey, the human expansion into the galaxy will also be covered “The film is about the discussion of terraforming -- taking planets and planetoids and balls of earth and trying to terraform, seed them with the possibilities of future life," he explained. The initiative will be led by the Weyland Corporation, an early iteration of the Weyland-Yutani Corp. that causes so many problems throughout the series. "Weyland hasn't joined Yutani yet, so they go and see Weyland," Scott said.”
Sounds like Scott has his work cut out. Plenty going on and at least it’s not a prequel for the sake of a prequel. He also went on the say the lead character will more than likely be a woman and he wants to talk to H.R. Giger (the original Alien designer) about a redesign as Scott feels the current Aliens are a bit worn out!