Actually, glutamine is the most abundant amino acid in the muscles, which means that it gets depleted after intense exercise. Therefore, it makes sense to replenish those Glutamine stores, which will lead to faster recovery. That's why I use the stuff. I do about 5 grams in the morning, 5 before my workout, 5-10 after my workout, and about 5 before bed on an empty stomach. Actually, if you throw some arginine alongside the glutamine at bedtime, it can actually help to raise GH levels, which will also help with recovery. Also, it's a good immune-system booster, which I can say first-hand as I rarely get sick anymore *knock on wood*.
If you're on a budget, best stuff I've found is the Body Fortress glutamine that you can get at Wal-mart for around $12 for around 90 servings. Compare that to a lot of other products that run around $70. Sheesh! Glutamine's glutamine, and Body Fortress has worked just fine for me!