Foam rollers or other similar things can help for sure.
I just wanted to post the *correct* way to stretch the ITB, because last year my physical therapist told me that all the ways I thought was correct for stretching it really hit other stuff like the hip flexors.
Stand near a table or counter that's fairly high up on you--probably no lower than low-hip height. Stand with it to your side--this will be the side you are stretching. You should be able to put your hand on it from your start point
Let's say you're starting with stretching the left side. Take your left foot and cross it behind the right, turning the foot so that you're resting on the left side of it. The left foot shouldn't be right behind the right but back some too, maybe a foot. Bend your right knee, lowering yourself using your hand on the table to balance, until you're feeling the stretch, no more than when the rear (left) leg makes a 45 degree angle with the floor. This is why you rest on the left side of the left foot--so that leg is straight. Be sure your hips stay aligned. Do not lean with your upper body or at your hips (this is why you bend the right leg). It may help to stand in front of a mirror. Hold for 20-30 seconds. Repeat a few times.
Turn around and change legs.
Sometimes, it's hard to feel the stretch, which is why I cautioned not to go too far to where you might strain something else. If you feel it, you'll mostly feel it up at the hip attachment area.
The best thing that works for me when the ITB gets really knotted up in the middle is to get a deep tissue or myofascial release massage. Unlike rollers, someone else is mashing on me and I am not inflicting pain on myself. So I'm less likely to be a wuss about it and the knots really get cleared.