The vision is a mix of symbols: Departure part(upper floor) in the waiting area represents Death, passing to the plane represents joining the Others, the area is the Island. The Island can only be escaped via death (upper floor) or by joining the Others (the plane).
In Locke's vision, while he's riding to the top of the escalator, a chain noise can be heard in the background; the same sound was emitted by the "Monster" when it dragged Locke through the jungle. It is likely that the sound foretells the role of the monster in the death of Mr Eko.
"Bringing the family back together" refers to the Shephards, i.e. Jack, Claire, Christian, Aaron and presumably Jacob.
Ben working in the lowly position as a security worker foreshadows his true insignificance (as revealed in The Incident).
"Going to help you find your way again, so you can bring the family back together" was in fact foretelling the events of Locke having to bring the Oceanic Six back from off the island.
The whole vision was foretelling the outcome of Season 3. Such as "They'll (Claire, Aaron and Charlie) be fine, for a while" was showing how Locke did not have to have much of an impact on Charlie's death. "Desmond is helping himself" this refers to when Desmond told Charlie that he had a vision of Claire and Aaron boarding a helicopter, and he had to die for it to happen. However, Desmond could have seen himself board a helicopter, and saw his rescue as a priority over saving Charlie, hence he was helping himself.
It's possible that Locke's dream wasn't meant for them to simply find the plane, but to find the Pearl Station. The plane was meant to lure someone up the side of the mountain and look down to see the Question Mark etched into the ground at the base of the mountain. Boone probably failed to see the Question Mark because he was preoccupied with examining the contents of the plane.
Both Locke and Eko's dreams could be a result of their contacts with the monster - having it somehow effecting inactive parts of their brain perhaps.
"...discovers Eko's stick coated in blood. Boone, now also covered in blood, tells Locke: 'Clean it up, John. They've got him. You don't have much time'." It can now be surmised that Boone was not talking about Eko. When he says "they've got HIM" Locke's premonition was referring instead to Anthony Cooper. This might shed some light on why Locke's going around blowing up stuff. He's "cleaning it up."
Locke looked a little too surprised to see Anthony for him to have known before hand about his being on the island. Locke's blowing things up for some other reason.
Boone did refer to "bringing the family back together" in the sweat lodge. This could have been a subtle hint towards Anthony Cooper being on the island, but Locke may not have understood it at the time.
"they've got HIM" could also correspond to Jacob being trapped within his spooky house, because he later obviously begs Locke to "help" him.
Locke's dreams indicate who will die next: in his first dream we see Boone, who dies when the plane falls down the cliff, in his second dream he is like Eko seeing Yemi, Eko dies a few episodes afterward, and during his third dream Charlie is waiting outside the tent, Charlie dies in the following season finale. All dreams take place when Locke is somehow handicapped (can't walk or speak). Maybe the Island always demands a death in exchange to recover Locke?
Each of Locke's dreams are Jacob's adversary's way of manipulating Locke. All are designed to maneuver Locke into more and more trust/fail situations, eventually bringing him to the point where he can be killed and "resurrected", allowing the loophole for Jacob to be killed. The Adversary has been misdirecting Locke from the beginning, in anticipation of using him to kill Jacob.