Planet

My theory is that they're not on LV-426, the ship crashing is not the derelict in Alien and that Prometheus will really be a stand alone movie. The Jockeys I think have based on different worlds and store their goo in different temples of theirs around the galaxy. The place we go to in Prometheus will be one of their bases. I think the only tie in to Alien will be that a Space Jockey (yes, I think only one) will be involved and that the Prometheus crew will mess around with the Jockey's goo and create something dangerous. The Jockey will view this as a threat in that the humans are using their material and set out to destroy the humans on Earth with something (probably not eggs but the stuff the Prometheus crew started) and the Prometheus crew will be stopping them. I don't think we'll wind up with dead Jockey, hole in chest and cave full of eggs.