You don't need to be premium Yahoo mail user to have access to POP and SMTP.
Hikaru Kaze above also use it like I do.
Regular accounts have POP and SMTP, you just need to enable it from your Yahoo account.
Goto option, pop & forwarding and select allow your Yahoo! Mail to be POPed. Remember to save changes.
Incoming Mail Server (POP3) - pop.mail.yahoo.com (port 110)
Outgoing Mail Server (SMTP) - smtp.mail.yahoo.com (port 25)