My own experience with Creatine:
Hardcore power bodybuilding (drug free, relax) and running about 4 miles twice a week while taking creatine: Drove to the top of Haleakala on Maui (10,080 ft altitude) and was puffing and panting while slowly walking up and down the stairs to the observation hut.
Not taking creatine, still hardcore power bodybuilding, a year or so later, no aerobic training whatsoever: Drove to the top of Haleakala and was running up and down the stairs all over the top region like a gazelle.
Creatine helped me be stronger, do more sets and reps (I noted a next-DAY increase in power when I first started using it) for weight training. For aerobic work, however, it seemed to have the opposite effect. I was taking large doses of it, though, and I weighed around 260-270 lower-than-the-average-person level of fat at the time.
Deadlift was up around 495, squat around 315 at this time.
When I used more moderate doses of creatine, I could jog 10.5 miles at a bodyweight of 270 at sea level.
I have never specifically tried it to increase my aerobic endurance or such. It WAS fun having the steroid users ask me what I was on, however.