Psionic Dabbler [Multiclass Encounter]

Heroic Tier
Prerequisite: 4th level, any class that doesn’t have the Psionic Augmentation class feature, any class specific multiclass feat for a class that has the Psionic Augmentation class feature
Benefit: You can swap one of your encounter attack powers for an augmentable at-will attack power of the same level or lower from the class you multiclassed into. You can use that power once per encounter. You gain a number of power points based on the level of the at-will attack power: level 1-10, 2 power points; level 11-20, 4 power points; and level 21-30, 6 power points.

Published in Player's Handbook 3, page(s) 194.