If you have a Yahoo! mail account and would like to get messages via MS Outlook Express, you need to subscribe for Yahoo! Mail Plus. In this way you can set email delivery via POP protocol in your Outlook Express. However this is not the only way to set this. As alternative, you can use additional tools that can integrate Yahoo! Into Outlook Express's POP account. One of such tools is YPOPs!.
First you need to install YPOPs! and open Outlook Express. Then go to "Tools > Accounts". Click "Add" and choose "Mail..." Enter your name and then go to Next. Here you need to enter your Yahoo! mail address, press Next and get sure that POP3 is selected in "My incoming mail server is....". Put 'localhost' as incoming mail server. If this doesn't work, put '127.0.0.1'. The same you need to set in "Outgoing mail". After pressing "Next" setup the Account name (Yahoo! mail address) and enter your password. Then just press "Next > Finish". In the Internet Accounts windows choose localhost. In Properties set Yahoo! Mail as mail account. After pressing "OK" you will be able to get messages from Yahoo! in your Outlook Express.
In this way you can save your money, as YPOPs! is free of charge. A few minutes of settings is all you need!
Remember to take a look at Kite WebMail Converter when you want to convert your Yahoo emails to PDF, DOC, TXT, TIFF, HTML files;)