ANY magic-user may open a door that has been wizard-locked, if he knows the key-rune.
MANY magic-users choose to add false key-runes to their locks. A false key-rune usually activates a hidden and perilous magical trap (all applicable saves allowed), but it can be used for any "spring-loaded" purpose its creator devises (teleportation to a hollow cyst in the earth, charm person or some other hypnotic effect, etc).
KEY-RUNES are usually a spoken word or phrase, but can sometimes be physical objects (a key made of fire, for example, or a certain metal).
P.S. Putting the finishing touches on the VANCIAN MAGIC SUPPLEMENT tonight.
NEXT UP: The Vancian Magic Companion -- More classic articles related to Magic in D&D, plus Gorgonmilk's guide to Magical Drugs