There were plans to drop several more nukes after the Hiroshima and Nagasaki bombings.
Interestingly Hiroshima was not bombed with traditional bombing so it was in pristine condition giving the Americans a chance to test the effects of the bomb. So in part the bombing of Hiroshima was just a test with real people.
Also it's good to know that allied P.O.W's also died in the Hiroshima and Nagasaki bombings.
http://en.wikipedia.org/wiki/Atomic_...a_and_Nagasaki
One rationale for the dropping of the bombs was that there was supposed to be a fierce resistance on the Japanese mainland. However, by that point the Japanese airforce with the last ditch weapons such as the Kamikaze-attacks had pretty much seized to exist. So it was just a fight between the remaining Japanese land troops on the continent against the allied air-, sea- and landpower.
Were there any fixed resistance points such as bunkers etc. on the Japanese mainland? Were the Japanese land forces in a state to continue fighting at that point? I've never seen any reliable info on these types of issues.