I really liked the soundtrack for this game, is there somewhere I can buy it? I can't seem to find it anywhere.

you dont need to buy it. all the sound files are in the game folder. all you need is a program that plays .ogg format, or just convert them to your prefered format

I paid them for the soundtrack, because they did an amazing job on it and deserve the money. Also, I'm not sure if copying it is legal, and they'd have given it as an extra if they wanted it to be for free. Copying it out of the folder feels like piracy to me.

well, in canada at least, copying your digital content for personal use is perfectly legal. so not piracy. dunno bout where you are. not that I'm criticizing you for wanting to give them money, that's a good thing, just that's how it is here.

You can buy a physical CD that came with the game's PSP LE on XSEED's official web store for $5. Just follow this link and scroll down to the merchandise section:
www.xseedgames.com/store.php

You will, however, need to fill your cart with enough orders to put the cost over $20, though. You can also get the poster and bracer pin set from the PSP LE for $5, also. You can get other LE goodies from previous releases for $5,also, to fill up a $20+ order.