ABC has apparently worked out a deal with Damon Lindelof and Carlton Cuse (the shows creators ?) in which the pair will remain with "Lost" for three more 16-episode seasons (4, 5 & 6) after which the show will end. All three seasons, the last of which will come in 2009-10, will air in unbroken blocks (in the US).
http://www.variety.com/article/VR111...goryid=14&cs=1