WordNet (r) 3.0 (2006):

motivational
    adj 1: of or relating to motivation

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "motivational":
   active, actuating, animating, causal, causative, compelling,
   directive, driving, impelling, impulsive, in motion, inducive,
   mobile, motile, motivating, motive, motor, moving, pressing,
   propellant, propelling, stirring, transitional, traveling,
   urgent