Creatine is best taken either:
1) Upon waking - where the body is most sensitive to absorption to load the cells with creatine for activity later on.
2) 30-45 minutes pre-workout - to further load the cells directly before the time where creatine will be most needed, this should be the priority time frame.
3) Immediately post-workout - when the existing creatine stores have been utilised from the high intensity workout and need to be replenished.