We used Gripe water with what seemed like some success with our first. I'm not sure what the active ingredients in the other products mentioned here are, but there is some debate - not to say controversy - over bicarbonate-based remedies. Basically, they work by lowering the acidity in the stomach, so some say they're just preventing/prolonging digestion and could screw up the pH of digestive fluids.
I can't find references right now, but I seem
As the linked page says
"getting a fussy baby to recall reading somewhere research that showed that just stop crying may be no more complicated than giving them sugary water seemed to help just as much...it some sweet-tasting liquid."