I havent used it for a while, but this is what I did per the instructions.
First go to Options, then account POP access and forwarding.
Check web and pop access
Configure your email program with the following settings
Server Settings
Incoming Mail Server (POP3): pop.mail.yahoo.com
Outgoing Mail Server (SMTP): smtp.mail.yahoo.com
using SMTP port 587
Account Name/Username: email
Email address: email@yahoo.com
Password: Your Yahoo! Mail password