Just looking over some spoiler/chat sites are here are a few interesting tidbits. I bolded everything that I just copied from elsewhere:
Rosa's story about her missing husband will be touched upon before the end of the season. So far the show has really left it open whether there are more survivors on the missing sections of the plane.
A question was asked about the time period that seems to be mentioned on the show each week. Paul said that they want the viewer to be very aware of the amount of time spent on the island. The entire first season will take one month of pseudo island time. And there's some speculation that the plane either went back or forward in time...I think this was prompted by Sawyer's book.
*When will pregnant Claire (Emilie de Ravin) finally go into labor? Get ready for an April 6 birthday. "She will definitely have that belly-bursting baby," Abrams says, but he adds a cryptic, "The story of Rousseau is something I would be nervous about if I were Claire." (Danielle Rousseau, of course, is the stringy-haired, haunted French woman who confessed to killing her "lost" child, Alex.)
*Also in that episode, Julie Bowen (ED) appears in a flashback as one character's fiancee. And Jack (Matthew Fox) wrestles with self-doubt as he struggles to save a fellow castaway injured in the March 30 episode.
*And what of Abrams' vow that one of the 14 major characters will be knocked off by the end of the season? He's sticking to it. "Given how scary that place can be, that no one would lose their life would be a cheat," he says. "We knew from the very beginning that we would have to do this. The question was always who and when."
*Lidenlof's early word on the finale is that, despite rampant rumors to the contrary, it won't reveal what caused the crash of Oceanic Airlines Flight 815. But viewers might not even notice, what with a promised jaw-dropping cliff-hanger. "It's gonna rock people's worlds," Lindelof says excitedly. "[It will be] the 'Who shot J.R.?' of LOST. We want people talking all summer long."