On a guitar, what keys correspond to different capo positions?
I've long had this question. I know some music theory, but I can only get a vague idea as to the progression of keys when moving the capo down a guitar's neck. I'm fairly certain that the guitar is in the key of E minor when no capo is used, but that may be wrong. When playing some songs, the instructions for capo position aren't something like "Capo on fret 3", but, instead, "Capo: C Major" or "Key: C Major". I've tried to find a description of this online, but the closest things that I've been able to find are descriptions of how to transpose chords to different keys. Any help is appreciated, and I wouldn't be surprised if I had some gross conceptual error.