I recently added an article to my website in which I talk about when to take creatine and the loading phases and maintenance phases. I know some don’t bother with this, but, I know many do.

Immediately before your workout is not the best time to take creatine.

First, large shifts in body fluid during exercise should be avoided at all cost. They could severely compromise exercise performance and even prove hazardous.

Secondly, less glycemic foods are a preferable food source prior to exercise because they provide cellular energy more steadily. On the other hand, highly glycemic sugars (like those taken with creatine) should be avoided prior to exercise because of the sudden crash in energy levels they cause.

Lastly, creatine needn’t be “fresh” to work. Once the muscle stores are full, creatine is stable until degraded. Therefore, the stores don’t need to be replenished immediately before exercising.

During your workout?

One study showed that taking creatine during your workout hampers exercise performance. This is probably due to the effect of dehydration on exercise performance.

Before and after your workout?

Don’t supplement to frequently. Supplementing both before and after exercise may be counterproductive because of the inhibition of creatine transporter activity that may still persist from the previous feeding.
The short answer:

The best time to take creatine is immediately after your workout when the metabolic state of skeletal muscle is most receptive to insulin-mediated uptake of creatine. Further capitalize on this situation by taking creatine with fruit juices (at least 16 ounces) that contain simple sugars such as glucose or dextrose.