A fighter's mark does not allow it to stop attacks unless he kills the target. A fighter's mark gives -2 to attacks and allows him to make a Melee Basic Attack as an immediate interrupt against an adjacent enemy who shifts or attacks a target other than him.
A fighter gets a bonus on Opportunity Attacks, regardless on if the target is marked or not.
Combat Superiority: An enemy hit by your opportunity attack stops moving, if a move provoked the attack. If the enemy still has actions remaining, it can use them to resume moving. [PHB pg 76]
Using this ability, a fighter can stop Charge attacks by effectively rooting an enemy in place before they can reach their destination. This would likely also work on any specific power that had movement before the attack as a single action, but only if the creature can not longer reach the target.
Immediate interrupts do occur before the action, while reactions happen afterwards. Note, you only get one immediate action per round.