(Started this new thread because it's about the future of Lost, not about season #3.)

An interesting (and lengthy) article at this link from CNN's website:

"Three days after the controversial finale of "The Sopranos," the two creators of "Lost" on Wednesday promised that their hit ABC drama would not conclude in similarly murky fashion. "We will not be ending with a blackout," said Carlton Cuse, referring to the black screen that delivered an unresolved ending to HBO's mob drama.
"He and Damon Lindelof told electronic-media professionals at the annual Promax/BDA conference that they fleshed out a plan for the for the last three seasons of "Lost" during a recent writers' "minicamp." "Lost" will end in spring 2010 after 48 hourlong episodes, 16 per season. Lindelof said "Lost" has to move from asking more questions to answering the questions posed during the series' run.

"Cuse said the first season was about the Oceanic Flight 815 survivors landing on the island and realizing they weren't going to get rescued. The second season was about the hatch, and the third season was about the Others. "Next season, well, we'll talk about that later," Cuse said.
"They said they realized almost immediately that adding Nikki and Paulo was a mistake, even before the viewer outcry. Many of the scenes they shot would get cut on the editing room floor, not because of the actors but because they were concerned about how they fit into the story. Lindelof said that it was a lesson for the writers to stay true to the show's vision even if the viewers don't seem to like it. "We buried them alive," Cuse said of Nikki and Paulo. "OK, you guys don't like Nikki and Paulo, there."

Much more in the article at the link above.