Are you paying for Yahoo's "Yahoo! Mail Plus" level of service? If not, then you can't use anything other than the web mail interface.

If you *ARE* paying for Mail Plus, then you want:

POP3 server

incoming server: pop.mail.yahoo.com

outgoing server: smtp.mail.yahoo.com

user name: (your Yahoo ID, basically your email address minus the "@yahoo.com" bit.)

password: Hopefully you know this.

You will also have to do the advanced settings, and turn on 'outgoing server authentication'.