i have read some articles about mda and mta but still don't have a hang on it.

what is exactly is the difference between a mda like fetchmail and a mta like sendmail.

in my computer, do i have to have a mta installed? if im using Apple Mail to send messages, is it using a mta application in my computer to send the mail? where does it send the mail?

and if i receive mails with it, does it receives it with mda installed in my computer?

would be great if someone could explain how it works for me, or give me good links to good tutorials.

thanks