Some indicators that time travel/warping is involved:
In the last episode, the polar bear and dharma sign in an archaeological site in the Tunisian desert.
there was an episode with Desmond last season after the explosion where he was experiencing parts of his life that he had already gone through, and there was a woman in a shop that he was in who seemed to know what was going on and told him that he had to do things a certain way.
In the scene at the beginning of season three where Russeu's daughter's boyfriend was being forced to watch scenes on tv you can hear a voice that says "Only fools are enslaved by time and space."
A character was reading the stephen hawking book "a brief history of time".
I'm sure there are tons more, but those are the only ones I can remember right now.
As for shows paralleling Lost, back in the early 90's it was Twin Peaks. I was too young to watch it back then, but watching it later it seemed very odd to me that people were fascinated by this show. Don't get me wrong, I love it, but it is just so damn weird (hell, it IS done by david lynch).
It has extreme melodrama like a soap opera, random funny momements thrown in seeminly haphazardly, very dark and disturbing scenes, extremely bizzare characters who have strange speech patterns, one armed men, bob, backwards talking midget dreams, a giant, and owls who are not what they seem.
Weirdest show ever, though brilliant if you like that sort of thing (which I do). As bizzare as it was, people were fasnicated by it, and it has become THE cult show (though Lost I think is eclipsing it...). Hell, I can think of two simpsons episodes that contain references to it off the top of my head. Last weeks episode of Lost even had a reference to it in the exchange between Lock and Sawyer and their discussion of Walt.