From my own experience overcoming chronic ITB problems:
Stop running for a couple of weeks and use anti-inflammatory medicines if you can tolerate them; give your IT band time to settle down.
Then do as many of the following as you can manage: -regular ITB strengthening exercises such as described at:
http://www.pponline.co.uk/encyc/0168.htm -temporarily reduce weekly mileage and longest runs from wherever they were when the injury struck -change to a different running shoe -avoid running consistently on the same side of slanted surfaces, such as cantered roads -study your training records and consider whether you have increased weekly mileage too rapidly -for the moment, choose softer running surfaces over harder ones (grass/dirt/gravel over concrete/asphalt), but also consult discussions on this newsgroup about how to run more softly in general -learn as much as you can about running form and whether you are over-striding, landing generally on your heels, etc. -finally, and this probably doesn't apply to everyone the way it did to me