i'm not applying yet but when the time comes get your hands on the MSAR (medical school admission requirements) . it's published by the aamc. that's probably the best way to start. it gives you important info like schools that screen, in-state/out-state applicant numbers, tuition, curriculum description, etc. your premed advisor should have a copy otherwise you could get it from aamc.org or from amazon (a good chunk of change but absolutely ESSENTIAL). everyone's list is gonna be different depending on what they're interested in. MD or DO? research? primary care? competitive specialty? it's all gonna depend on what YOU want
addendum: MSAR is for US/Canadian allopathic, MD schools
there's a similar publication made by aacom for osteopathic schools. you can request one to be sent to you or download it in PDF from the website