This is all copied from various sites because I am too tired to type right now.
IT band syndrome
Excessive friction between your Iliotibial Band and your knee (or hip) bone. This causes a sharp pain at either the side of your knee or the side of your hip. Usually caused by increasing your running or biking too fast and/or with bad form, but is also associated with weight-lifting (standing squats), court sports (raquetball, tennis, handball, etc) and even pregnancy.
How to diagnose ITB syndrome
As mentioned, a key aspect of ITB syndrome is lateral knee tenderness.
As often as not, the pain won't really hit home until the first one or two miles of a workout have been completed ('Iliotibial Band Friction Syndrome in Runners,' American Journal of Sports Medicine, vol. 8, pp. 232-234, 1980). Once it starts, the pain tends to be persistent if you keep going - and frequently gets worse during downhill running (and while walking down steps). The discomfort may radiate up and down the leg, but - strangely enough - the pain will often almost disappear if you stop running and begin to walk slowly and with short steps.
If you have ITBS, a unique examination called the Noble compression test will often be 'positive'. As you lie on your back, your doctor will place his or her thumb over the lateral epicondyle of your troubled leg (the lateral epicondyle is the hard knob on the bottom, outside part of your thigh bone). With the thumb on your epicondyle, you will actively flex and extend your knee. If maximal pain occurs at about 30 degrees of knee flexion, watch out! You probably have ITB syndrome.
The reason your knee 'cries out' during this test is very simple: when your leg is straight, the ITB lies in front of the epicondyle; as you flex your knee the ITB actually passes over the lateral epicondylar surface. As you repeatedly flex and extend your knee (as you would during running), the ITB keeps moving back and forth against the epicondyle; if the ITB is inflamed and swollen, the friction associated with this epicondylar 'rub' can produce quite a bit of pain, especially when your doctor is forcing the ITB to be in close contact with the bone. Similarly, if you have ITB and you stand with all your weight on your affected leg and flex the knee to about 30 degrees or so, you will probably feel a lot of pain if you apply pressure to the outside of your knee.
(As an aside, walking 'stiff-legged' with the affected knee locked in place will often eliminate most of the pain, because it keeps the ITB from rubbing back and forth against the epicondyle.)
In truth, though, ITB problems don't always occur at the knee. Pain may also be present below the knee, where the ITB actually attaches to the tibia, and discomfort may also occur much higher up - in the tensor fascia lata itself or in its tendinous connection with the hip. Many runners recall an especially intense or prolonged workout just before their ITB troubles started. Often, ITB strikes near the beginning of the cross-country or track season, when athletes are attempting to step up their training loads. Having 'bow legs,' excessive leg-muscle tightness, a leg-length discrepancy, or very pronounced foot pronation can all increase the risk of ITBS.
Here are some sites with IT band stretches. Link 1 Link 2 Link 3
Also, deep tissue massage helps release the IT band. Lay laterally with a rolling pin or pool noodle under IT band. Roll back and fourth to massage it. Try to relax in the process.
I had deep tissue massage that left huge bruises on my legs, but it helped release my IT band and my knee felt a lot better. Now I just maintain it with stretching.