History
Dual talent specialization was first introduced to "World of Warcraft" in the 3.1 patch, "Secrets of Ulduar." Dual talent specialization was available to any character who had reached level 40 or above and cost 1,000 gold to unlock, making it inaccessible for players who lacked the interest, the time or the ability to earn a large amount of gold. The situation remained the same until the release of the "Cataclysm" expansion, when the price was reduced to 10 gold and the level requirement lowered to 30.
Obtaining and Using Dual Talent Specialization
Once your character has reached at least level 30, visit a class trainer in any capital city to purchase dual talent specialization. Click the "I wish to know about Dual Talent Specialization" dialogue option, select "Purchase a Dual Talent Specialization" and press "Accept" on the confirmation window that appears. Press "N" to bring up your talent screen, click the second tab on the right of the window and click the "Activate" button, then distribute your talent points, apply your glyphs and arrange your abilities on your action bars as normal. To switch between specializations, select the tab that corresponds to the currently inactive specialization and click "Activate."
Benefits
Dual talent specialization can be beneficial to players who want to cover multiple roles or participate in different types of content. For example, a player who commonly performs the healer role in groups could set his second talent specialization to take on the damage dealer role and be able to efficiently kill enemies while questing alone, while another player might tailor one spec for player vs. enemies (PVE) content and the other for player vs. player (PVP) battles.
Restrictions
You may not switch between talent specializations when you are in combat or when you are in an arena or battleground, except for when you are under the "Preparation" buff before a battleground begins. Switching between talent specializations will completely drain your resource bar and remove any buffs you may have cast on yourself or other players.