I just did my first BG in Warsong Gulch, I got this unique item called the Warsong gulch medal of honor or something like that, what do I do with it???
If you get three of them you can turn them in for a quest reward of xp... after the first turn in you can still do the quest, but you get no real xp. With the new PvP reward system you are better off holding them to purchase better gear later on.
They are along the same lines now as any kind of item you have to cellect for a quest. You gather up enough to 'complete' that quest and get a prize.... awesome blues, and amazing purples.