Interesting news. Ridley Scott's two back-to-back Alien prequels are still on track to begin filming in March for release in 2012 and 2013. The first film has the somewhat non-terrifying title Paradise (possibly Alien: Paradise) and chronicles an encounter between a group of human explorers and a terrifying alien lifeform, whilst the 'space jockey' extraterrestrials (a corpse of whom was found in the first movie) also play a role.
Actors being lined up for the project include Michael Fassbender and Michelle Yeoh. A previous attempt to cast Leonardo DiCaprio has apparently fallen by the wayside (Scott and DiCaprio apparently couldn't get their schedules to align without delaying the two movies by a year or more) and it's been revealed that the movie will feature a totally-CGI creature called 'Engineer 1', presumably one of the space jockey creatures.
I'm still not sold on the need for these prequels, and I hope that Paradise is a working title as it doesn't sound very interesting.
UPDATE: 20th Century Fox have stated that Paradise is not the title and that they envisage the project as just one film at this time. Considering this is contrary to all previous reports on the project, it'll be interesting to see what the full story is here.