Oh, me me!! Not something I enjoy talking about so much, but I got diagnosed w/ IBS a couple yrs ago. I was on some meds for it for a while (they're supposed to help regulate your colon) but stopped taking them because they had a lot of side effects.
What has helped me a lot is adding in more fiber to my diet (Fiber one cereal added to my oatmeal, other cereals, etc) & drinking a LOT of water (at least 120 oz a day). Also, there are things that can be triggers- for some it can be too much caffeine, MSG or other additives, high fructose corn syrup (this is a trigger for me!), dairy, plus stress, PMS, etc. Eating healthy helps a lot also. If I eat too much junk, I can definitely tell!!
And yes, I am a runner (training for my first marathon this weekend!). I haven't had any problems w/ it while running, I honestly think running helps keep things *regular* for me.
Have you been diagnosed by a Dr.? There are also a lot of websites w/ info in IBS. It's a lot more common than I thought when I first got diagnosed.
HTH & good luck!