This seems to make the most sense regarding what Sayid is up to.
A short time after Sayid departed in the helicopter, he will cause (either intentionally or not) the bearing to be altered and will leave the island at a different bearing that the one the helicopter came in on. This will cause the helicopter to return to the world a year or so into the past. Once there, Sayid will locate Ben and use Ben's knowledge of the "enemies" working against his friends to make a list of people that need to be assassinated in order to correct future events.
This explains why none of Sayid's targets recognize him yet, and also why they do not know Ben's identity yet. In the past, he hasn't yet done whatever it was that identified him to his enemies. They desperately want to learn his name from Sayid so that they can stop whatever it is he plans to do in the future to thwart them.
This also explains all of the strange currency and passports in Ben's possession. Ben has to be able to travel between several times in order to learn of certain events as they unfold.
Theory by Quickclay
A short time after Sayid departed in the helicopter, he will cause (either intentionally or not) the bearing to be altered and will leave the island at a different bearing that the one the helicopter came in on. This will cause the helicopter to return to the world a year or so into the past. Once there, Sayid will locate Ben and use Ben's knowledge of the "enemies" working against his friends to make a list of people that need to be assassinated in order to correct future events.
This explains why none of Sayid's targets recognize him yet, and also why they do not know Ben's identity yet. In the past, he hasn't yet done whatever it was that identified him to his enemies. They desperately want to learn his name from Sayid so that they can stop whatever it is he plans to do in the future to thwart them.
This also explains all of the strange currency and passports in Ben's possession. Ben has to be able to travel between several times in order to learn of certain events as they unfold.
Theory by Quickclay
