Microphone Use

Hey all!
so i just bought a microphone [USB desktop, Logitech] and i was wondering-
is there some way, i could say something in the mic, and hear it through the speakers on the mac
kinda like at a concert or something, the singer sings into the mic, and then it's amplified by the speaker.
i dont know if this makes sense, but if it doesn't I'll try one last simplification:

Voice --> Mic --> Computer --> Computer Speaker
like i don't want to record anything, i just want to hear my voice

let me know if this doesn't make sense...


EDIT: here is a better wording:
Use a USB Microphone and hear it live through speakers