Gendou's Anime Music - Search: "Alchemist"
They have about 40 FMA songs up right now, including a lot of instrumentals and even some single b-sides that aren't used in the series, but they rotate them once in a while, so if you're looking for something that isn't there, you can request it. You need to register, but it's painless. ;P
EDIT: Eh, scratch that, apparently kaitou_marina has just about everything right here. Coolness. =3 *slinks out of sight*