I just started watching this show last week as well, and I'm really looking forward to this Wednesday. According to a guy at my work (who's seen all of the episodes to date), one of these next two episodes will deal with Terry Quinn's character - he's the bald guy on the beach who was explaining backgammon to the little kid. I've loved Terry's other major roles, as Peter of the Millennium Group in Millennium, and as the evil Santiago in Harsh Realm. I can't wait to see his backstory in Lost[/].
Oh, and as for the big mystery of the island, my own guess, with the admission that I'm only basing this on the information presented in the first two hours, is that this is some sort of "genetic experiment island," kind of like "Jurassic Park" or "The Island of Doctor Moreau." Yeah, it's probably wrong, and there will no doubt be further information in upcoming episodes that contradict this guess, but right now it helps explain why there would be a polar bear living in a subtropical environment, and could explain the "monster" that ate the pilot - okay, maybe there aren't dinosaurs being grown from DNA taken from prehistoric insects trapped in amber, but there could well be Komodo dragons grown to enormous proportions, just to see how far mankind can play around with DNA.
That's my current theory, anyway. Somewhere on the island is/was a genetic laboratory, and the mad scientist(s) behind the experiments may still be around. I'm looking forward to being proven wrong, though.
Johnathan