From the Compendium, under 'Intimidate': Action
: Standard action. Outside combat, the DM might allow an adventurer to make the check as part of another action.
Opposed Check: Against a monster’s Will. (Adventurers can also try to intimidate DM-controlled characters.) The monster gains a +5 bonus to Will against the check if it is unfriendly to the adventurer, or a +10 bonus if it is hostile. If an adventurer attempts to intimidate multiple monsters at once, make a separate Intimidate check against each monster’s Will. Each monster must be able to see and hear the adventurer.
If a monster doesn’t have defenses specified, the DM should select an appropriate DC from the Difficulty Class by Level table, usually a moderate or a hard DC of the adventurer’s level.
This check fails automatically against a monster that is immune to fear. The DM might decide that this check also fails automatically against a monster, such as a golem or a skeleton, that acts under some form of magical compulsion.
Success: The adventurer forces a bloodied monster to surrender, gets a monster to reveal a secret, or cows a monster into taking some other action. This skill is not mind control, so a cowed monster is unlikely to take any action that would cause immediate harm to itself.
Failure: In combat, the adventurer can’t try again against the monster during the same encounter.
Target Becomes Hostile: Whether or not the check succeeds, using this skill against a monster usually makes it unfriendly or hostile toward the adventurer.
This is printed in the PHB under the Intimidate skill.