Battle.net Mobile Authenticator for Windows Phone 7 Devices
Blizzard has released a Battle.net Mobile Authenticator compatible with Windows Phone 7 devices on the Windows Phone Marketplace. The Authenticator adds an extra layer of protection to your b.net account by providing you with a one-time password that you use in addition to your regular account name and password when you log into b.net to play StarCraft 2 or World of Warcraft.
Do be aware, though, that if some misfortune befalls your phone, you’ll be locked out of your b.net account — this happened to a friend of mine. He was unable to play WoW or SC2 for a couple months, but that’s only because it took him that long to contact Blizzard technical support, who were quick to resolve his issue.
More information can be found on battle.net.