Here's the trailer for the movie Prometheus, which I'd initially heard was a prequel to Alien.
However, based on the Wikipedia article, it looks like it'll be about human scientists searching for alien involvement in the early days of human history. I think the aliens in question are the "space jockeys" whose ship carried the eggs that caused so much trouble in the first and second Alien films.
As I've said earlier, I'm not a fan of the ancient-astronauts theory, although the aliens-help-humans variant is not as bad as the humans-are-aliens version. A member of my message-board whose handle is 9-Fanged Hummingbird came up with the following, which points out both how absurd the idea is and the racist implication that certain cultures need alien help:
The ancient aliens hypothesis relies on the idea that these guys who mastered space travel are watching us and helping brown people to build tombs for their kings out of stone for god only knows what reason. Also, the aliens pile up random rocks in other places just because.
Seriously, to a civilization like that of the "space jockey," early humans would be little more than animals. Why bother with us?
Still, it looks like it'll be an entertaining film. Between that and John Carter and a bunch of other films slated for 2012, I think I'll be spending a lot more time at the multiplex.