I'm working with a non-profit organization at the moment and we're planning to conduct a survey on ~93,000 to find certain attitudes and the correlation associated with them. We're hoping on having our results being published in a reputable journal if possible, because we've done a lot of research and background reading to have a pretty solid study design written down. Is it necessary for us to have IRB approval to publish in a reputable Psychology/Educational academic journal? Additionally, even if it's not explicitly stated in the manuscript guidelines, are there "unspoken" rules about stating IRB approval before submission?
Most reputable journals in fields that involve human subjects research require that authors state (often in the article itself) that the study received approval from an IRB or the national equivalent in some other country.
As researchers that aren't affiliated with an organization that has its own IRB, you're in a bit of a bind. There are independent Review Boards that can be contracted to provide oversight of research conducted outside of a normal institutional setting. These are used for example in some drug company sponsored clinical trials. You would have to contract with such an IRB to have your project reviewed and supervised.