Well, for me it was just a matter of getting my body use to drinking while I was running. I do sip small portions though and space them out a lot. I can't run by an aid station and drink a cup of water.

For longer runs, I do eat Accel Gel (has a 4:1 Carb/protein ratio). It works for my stomach... but again... I don't down the whole gel at once... I slowly eat it over about 10 minutes. I do this to ensure that I don't dump too much in my stomach at once.

Good luck!