The power Wizard's Wrath contains the following text:
Effect: The burst becomes a zone of arcane energy that lasts until the end of your next turn. You gain combat advantage against targets in the zone, and they lose all immunities and resistances against your attacks.
Slightly different, but similar is the feat Paladin's Truth:
When you attack a creature marked by you, you ignore that creature’s resistances and immunities.
Obviously this applies to instantaneous things- a monster immune to fire would take fire damage, for example. What about things that continue? If you had, for example, a power that Dazed until the end of your next turn, or for that matter (Save Ends), and attacked an enemy who was Immune to Dazed, would they remain dazed?