Numbers from Prior Elections

Where can I find numbers for prior elections (going back as far as has been recorded) in terms of # of registered voters, # of popular votes for Candidate A, B, C, etc. and corresponding number of electoral votes?

You can try this one, for presidential elections only (which is what I assume you want, given your mentioning of electoral votes):

http://uselectionatlas.org/USPRESIDENT/frametextj.html

Awesome, thanks!