Semantics, if you have knee pain on the outside of your knee you very likely have ITBS. If you catch it early its not too bad but if you don't then you end like me when I was out for 5 months trying to recover.

Without a doubt buy a foam roller. Foam rollers come in different densities. I recommend the denser version, it hurts a little more to start but gets deep into the tissue. Roll your ITBand, quads and hamstrings. You can't really stretch your ITBand effectively with regular stretches, its just not going to happen. You should stretch the surrounding area (hips, quads, hammies). The foam roller as a form of stretching will work out knots. Regular stretching won't help at all for knots. It simply stretches the good tissue leaving the knots alone.

Look at exercises to fix muscle imbalances that you likely have. ITBS is usually related to weak glute or hip muscles and you end up compensating and stressing this band. For me it was obvious I did some glute exercises and the next day the glutes from the affected leg were obviously more sore than the other side. Most people have a leg length discrepancy of some sort which can contribute to this. Other factors can be shoes or the camber of the road.

Strengthrunning.com has a lot of good info and exercises, I would use it as a resource. Just catch it before you get deep knots or scarring so that you arent out for a prolonged period of time. I had to get regular massage therapy and went from a foam roller to a rolling pin to get deeper in. I never got better until I did that plus the strength training.