I've been suffering from ITBS on and off for a few years now. It's basically a pain on the outside of the knee, caused by a tight IT band rubbing against some bones in the knee. Very painful and crippling, you can't run through it, it's been the biggest hinderence in my progress.
I was going to physio for it, and they suggested I see a podiatrist.
Sure enough! I'm an overpronator. It's not uncommon, but mine was really quite bad... they did X-rays and showed me a lot about my feet that just wasn't right.
They took a plaster cast of my foot and ordered orthotics. I'm self-employed, so I don't have extended health coverage, and these were NOT cheap... $400 per set, plus $200 for the plaster form, and I needed two sets (one for everyday, one for running & cycling)... ended up at over $1000!
It was an easy decision, though, the podiatrist was telling me my symptoms before I could tell him... everything he said exactly matched my experiences, so he was either psychic or he had it right.
I finally received them a couple weeks ago... at first they felt pretty uncomfortable, but it only took a few days before I got used to them.
Running - I finally tried a few runs, and WOW, what a huge difference! I feel like my running style has completely changed, my push-off feels "complete", like I'm actually rolling off my toes properly and evenly. Best of all - no knee pain!
Cycling - same thing, it feels so much better, straight up and down with no wobble.
Walking - also great! I used to get sore feet and lower leg pain if I walked too much, but now I can walk and walk with no even a niggle.
I'm very excited, I think this has solved my problems. I'll keep at it and will post my results! But if you're suffering from ITBS, I'd strongly urge seeing a podiatrist, it just might be the root cause...