Worgchef over on the offcial boards has put up a guide for tanking. For those warriors in needof some help it'is worth a look.

Basics of Tanking

In WoW, “tanking” is an essential part of any PvE group dynamic. Tanking is holding the monsters’ attention upon one group member, generally who has the highest armor and hit points, so that the other group members can safely do damage and heal.

The warrior is ideally suited to the tanking role. Along with paladins, they can wear the strongest armor in the game. They tend to have the highest hit points. They have the greatest variety of agro management tools in the game.

The whole guide can be found here