Travel to Alterac Valley in the Hillsbrad Foothills. Outside of the entrance tunnel, find and speak with Lieutenant Haggerdin.
For the glory of Bronzebeard!
We are fighting a brutal battle in the valleys of Alterac. The cannibalistic Winterax trolls attack us from one side and the savage Frostwolf Clan from the other. Both must be exterminated in the name of King Magni Bronzebeard! The taking, culling, and turning of that land is a sovereign and territorial imperative to the kingdom of Ironforge.
Alas, soldiers do not grow on trees! Report to Lieutenant Haggerdin outside Alterac Valley to begin your tour of duty and honor amongst the Stormpike.