From Custom Fit Software:
Hotmail Popper is a small application that allows you to check your Hotmail e-mail account from a normal POP mail client (such as Eudora, IncrediMail, Mozilla Thunderbird, Opera, Netscape, etc). Unlike standard mail accounts that allow users to retrieve their e-mail through a POP mail client, Hotmail can normally only be checked on the Web. With Hotmail Popper, you can use your favorite POP mail client to retrieve your e-mail from your Hotmail account. In addition, Hotmail Popper allows you to send e-mails through Hotmail's service, as if it was a normal SMTP (outgoing mail) server.