It depends if you mean a glide bomb or a freefall bomb. If you mean a freefall bomb it is easy to get the distance, you must know only the altitude and IAS of the plane.
You will get the time of the freefall of the bomb from here: h=1/2g*t^2 where h is for height (altitude), g is a gravity constant (9,81 approx) and t is the time of the freefall. And when you know the time, calculating the travel in a horizontal plane is a piece of cake. It is s=v*t where s is a distance you want to know, v is a velocity of the plane and t is the time of the freefall. But the result will be only a theory, in real life you must also calculate with the airdrag, which affects the result very much at high speeds and it also limits the speed of the freefall. The result you will get is simplyfied and is valid only in vacuum :D