Halo Reach: Deliver Hope

How would I go about legally acquiring the theme used in this video ofr my iPod?

What do you even mean by requiring the theme? You mean the video? Because you can just download that off youtube somewhere.

He means the theme(music) in the background it’s a peaceful tune.
You could get the Reach OST(If I’m not mistaken)

It’s not on the OST. I bought it when it first released.