Are you certain they compete for receptors at the same time? While my knowledge on the specifics of human physioglogy or biochem don't extend far past what information I have acquired in terms of making informed exercise selection and diet decisions (ie, not as detailed as knowledge of specific receptors), it seems a bit contradictory to me, not to mention that I would like to think I would've heard of something like this before if it were the case. To be certain, this would not be the first time i was woefully ignorant on such an important matter (hey, that's why I hang around here), but, while I can't recall the specifics, I was really under the impression that creatine adn glutamine went through quite different metabolic pathways and did not compete at the same receptors.

That being said, i've been fond many times in the past of taking a bit of glutamine with water about 75% of the way through my workout, creatine immediately after, glutamine with the meal following the creatine intake, glutamine again before bed (with milk in the past, in the hopes it would be absorbed slightly slower than with water) and then again when waking in the early am to take a leak.