My first post and it involves piracy... (probably)
Hopefully this will save you some time. Googling for a download for this is totally pointless (unless Google led you here).
Download Lux Aeterna Remix
The link above should lead to a Two Tower's trailer remix of Clint Mansell's Requiem For A Dream theme music download. The original Mansell piece is called "Lux Aeterna" (I think... since variations of it are used throughout the RFAD score, it could be validly called a few other names... or perhaps not... eh, I don't know). Anyway, most people call the original "Lux Aeterna", but this Two Towers version goes by a few other names, which include 'Requiem For A Tower', 'Requiem For A Ring' and 'Lux Aeterna (Full Orchestral Remix)'. Whatever its name, it's fantastically rousing.
Go here for real information:
Wikipedia - Lux Aeterna
Here for info on the original composer:
Wikipedia - Clint Mansell
And here for The Two Towers trailer:
Youtube - The Two Towers Trailer