I just saw this on Lostpedia:

"Lost" co-exec producers Eddy Kitsis and Adam Horowitz have inked a mid-seven figure overall deal that will keep them on the ABC Television Studio island through 2010.
Three-year pact calls for the scribes to continue on "Lost," rising to exec producers by the second year of the deal. They'll also create and develop new projects for the studio.

The entire article can be seen at www.variety.com

now lets hope that they continue to deliver the goods

I've heard that's just backup in case ABC decides not to let Darlton finish the show on their terms.  Personally, I don't know that I'd want them to milk the story longer rather than end it in a satisfying way... it would have to be really compelling.

Honestly, I feel the show has maybe two more good seasons left after this one. Any longer and I think it definitely turns Gilligan's Island on us.

I truly hope Damon and Carlton get to end the show on their terms, but we've all seen what happens when the network has other plans.

Totally. I want the ending to be satisfying. But with all the elements and clues tied into the characters and the show, it makes you wonder "WHAT THE HELL ARE THESE WRITERS THINKING??!!"

I mean, look at the signifigance of the show. The characters, the plots, the flashbacks. They're all tied together in some mysterious, yet hopefully, plausible way.

It's just..... WOW!

well i don't 4 is enought to finish the show it would feel really rushed then, and six might be a bit much (not IMO though six would be alryt, no more though) so 5 might be the suitable amount of seasons to have, but if i had to choose from 4 or 6 i'd defintly go with 6...