Hey guys after several hours I finally got this Thunderbird Yahoo up and running and downloading email messages on yahoo...thank god!
Here's how I did it
Go here and Download the newest version of Webmail and the Yahoo Webmail Extension
Save these files to any folder or to the desktop
Open up Thunderbird and click Tools-> Addons->Installs
Once you click installs find the two .xpi webmail extensions and install them.
Check "Email account" and click next
Fill in Email address "email@example.com" and click next
Check "Pop" and make your incoming server 127.0.0.1 click next
Incoming Username "firstname.lastname@example.org" and click next
Name your tbird folder whatever you want and click next..
Your account should have been created....now go to Edit->Account Settings
Under your Yahoo email click "Server settings"
Make the Port 1025 and under security settings click "never" (you can fool around with this and see if you can get it to work under other security settings)....also make sure your Username reads "email@example.com"
Then click OK
Lastly go to Tools->Addons again and highlight Webmail and then click Preferences
Make the port in here 1025 as well and then click ok....restart Tbird again...
Now try downloading your mail!
Hopefully this works for folks here let me know if u run into any issues!
Someone else can chime in with the proper smtp settings..