The one that always works for me, got a ymail.com account:
Incoming settings:
Protocol: IMAP
Email-Address: your email address
Password: your password
IMAP Server: android.imap.mail.yahoo.com
Protocol-type: SSL
Server-port: 993
Outgoing settings:
Login required: Check
Username: your user name/email address
Password: your password
SMTP Server: android.smtp.mail.yahoo.com
Protocol-type: SSL
Server Port: 465
Other Settings, not tested (well they don't work with my phone, but others say they do):
Server:Port
imap.mail.yahoo.com:143 / 993
smtp.mobile.yahoo.com:587 / 465
pop.mail.yahoo.com:110
smtp.mail.yahoo.com:25
pop.mail.yahoo.de:995
smtp.mail.yahoo.de:465