irdeggman said:pg 4 of the Spell Compendium has captured the "rulings" from Sage Advice on the subject.
"Activating a spell completion item, activating a spell triger item, or drinking a potion is a standard action even if the spell from which the scroll, potion, or item is made can be cast as a swift action, In other words, it takes a standard action to drink a potion of quick march, even though casting the spell itself requires only a swift action."