Register an account on the Electronic Arts web site that is linked to your profile in Dragon Age: Origins. Play the Dragon Age Journeys mini-game at www.dragonagejourneys.com. Complete the indicated task in Dragon Age Journeys to unlock the corresponding item in Dragon Age: Origins.

Amulet Of the War Mage: Sign in to your EA account in Dragon Age Journeys.
Embri's Many Pockets: Save the Grey Warden Martine by completing The Missing Warden quest.
Helm Of The Deep: Unlock all five achievements in Dragon Age Journeys: The Deep Roads.