While reading an interview at TVGuide.com with Lost
producers Damon Lindelof and Carlton Cuse, I came across a side project
they had going.  As a fan appreciation move, Cuse and Lindelof
commissioned 16 posters by various designers and artists that they sold
in limited quantities (which have since all sold out of course) on the
website, damoncarltonandapolarbear.com. 
Therein you’ll find the various posters, including the one pictured
below. Speaking on said artwork and its potential clues, they had the
following to say:

Cuse: “I think you should look in there and there will
be a couple of clues to the final season that are embedded in that
poster. It will make a lot of sense once you’ve actually seen a few
episodes of the show.”
Lindelof: “You should look
at the poster and think of the things you’ve seen on the show, and then
whatever else is left, that’s a clue for Season 6.”

Regarding fan expectations for this final season, Lindelof said, “I think at this point, the nervousness is more based on how we’re so
deep into this season, that by the time the audience sees it, we’re
committed to our path. It’s been like that ever since we started
premiering in January and February. It’s like it’s too late to turn
back now. We’re feeling very confident about executing what our plan
was, and that’s all you can ever do.”

When pressed on which of the posters were their favorites, Cuse chose this Locke poster, while Lindelof favored this Hatch number.  Personally, I plan to grab some shrooms and check out this Hurley poster again closely. 

Trip on island artwork on the message boards.