Please explain the Passes of the Dead.....

I cannot understand why Aragorn wanted to find them and go through them, what actually happened or even where they should be on the ******* map!! Can someone please give a short explanation....?

The Paths of the Dead were a subterrenean passage under the White Mountains. They also happen to be haunted by the spirits of Men who had promised Elendil they would fight against Sauron at the end of the Second Age. They went back on this promise because they had secretly worshipped Sauron in the past. So they were cursed to remain in ME as ghosts until they could fulfill this promise. Aragorn, as Elendil's heir, was able to summon the spirits to fight on his side. They helped defeat the enemy fleet at Pelargir and thus fulfilled their promise and were allowed to depart. So the Paths of the Dead actually served two purposes: they gave Aragorn a source of "manpower" (or "spiritpower" if you will) to help in the war, and they also gave him a shortcut to Pelargir.

To find where they are on the map, it depends on which edition you have. I used to have an older paperback edition from the 70's (Ballantine Books) which had a close up map of Gondor and Mordor, and I believe Erech and the Haunted Mountain were marked on this map. I can't recall for sure and I no longer have this edition: I leant it out and never got it back. If you have just the general map of ME, look for the river Morthlond south of the White Mountains. Erech is marked on the map near the source of Morthlond, although it may be hard to see. The Haunted Mountain is not marked on this map, but IIRC it was in the mountains south of Edoras.

Eruve explained it pretty well.

The ghosts who haunted the Paths were spirits of Men who had gone back on their word to fight against Sauron. They were cursed to remain there until they fulfilled their oath. When Aragorn travelled the Paths, he called up the ghosts to help him. They fullfilled their oath and were set free.

As for why, they cut several day's travel between the Hornburg, Dunharrow and Minas Tirith (especially since Aragorn had seen the ships of the Corsairs and needed to drive them off, in order to bring men to the rescue of Minas Tirith).

yep, once Aragorn won Sauron at the PalantÃ*r mind-fight he saw all the war movements Sauron was preparing, and he became aware that it was necessary to stop the corsairs before they reached Minas Tirith, so Aragorn choose the faster way to intercept them. Also, the prophecy helped him to make up his mind.

They pretty much summed it up

Yeah, thanks guys. BTW, I finished LOTR today...started very early August.