The Blizzard Mobile Department released their first iPhone / iPod app recently, offering fans an alternative to secure their World of Warcraft accounts by replacing the physical Blizzard Authenticator with an iPhone. You can download the Battle.net Mobile Authenticator app off iTunes. Simply launch iTunes and type: Blizzard Authenticator. It will allow you to download it for free. The application will give you a random number that you must enter when login into World of Warcraft or entering your account webpage.
This app gives you an extra security that your account won’t be hacked and items stolen by gold farmers. A very nice guide with screenshots on how this app works can be found here.