I'm sure many of you have read, but aparently,

QUOTE:

"Jin is gonna be fine. I suspect that the difference between Michael's and Jin's survival is that Michael was trapped inside the hold, whereas Jin being up on the edge of the deck meant he had a chance to be blown clear of the ship. Emilie de Ravin will be on a holding contract with Lost for season five and returning in season six. Source: Kristin on E!Online"

I dont quite undersatand the bit about Michael - I assume he'll be back, because otherwise, his part in season 4 seems a bit pointless.

"Hey guys! I'm back! Call me Kev.... Oh sh#t! My legs have just blown off!"