About one week ago I was running on the treadmill and after about 5 minutes I felt a sharp pain on the outside of my left knee. I couldn't run anymore. There was no injury or inciting event. It just happened out of the blue. Since that time I haven't been able to run more than 10-15 minutes because the sharp pain starts at that time. If I walk straight-leg, the pain disappears. As soon as I bend my knee, it hurts so much. I have been running for approx 9 months and I only run 10-15 miles per week. I have been doing some reading and this sounds like ITBS to me but I wanted ask for advice from the runners out there about how to treat this type of injury and I'm wondering how long it may be before I can run again. I'm so depressed because I can't run. Can anyone offer any advice or helpful tips?

Thanks so much!

sure sounds like it.. As painful as it may be (I'm battling the same thing right now):
stop running for now
swim, on your back, using frog kicks
if you can tolerate it, take Ibuprofen (high-dose) w/food daily for ~3 weeks; ice it 20 min at a time, 2-3x day
don't sleep on your side (I slept on the other side and made that one worse)
here's some awesome sites that go into detail.
don't do what I did (started back running before completely healed) - I've been battling ITBS, now combined w/bursitis and gluteal tendonitis for >4 years...!

http://www.sportsinjurybulletin.com/archive/runners-knee.html

http://www.physsportsmed.com/issues/2000/02_00/fredericson.htm

hope this helps!
Don't give up and do the stretches 3-4x day!
When I started sleeping on my back (what a drag), with a pillow slightly under my bottom, without pressure on the sides of the legs, only then did I start improving.

If it doesn't get better, have it checked out to make sure you don't have another problem, like meniscus wear-down, stress fracture etc.
good luck,
Anne