Thunderbird Setup (Windows Users)
3. Click on Email account radio button and click the Next > button.
4. Fill in your personal information as shown below. Substitute yourdomain for your actual domain name. Click on the Next > button.
5. Fill in the information as shown below. Substitute yourdomain for your actual domain name. Click the Next > button.
6. Enter your email address as shown below. Substitute yourdomain for your actual domain name. Click the Next > button.
7. Enter a name for the account. You can specify any desirable name for the account. Click the Next > button.
8.Click the Finish button to complete the setup of your new e-mail account.
Article From: http://www.thedomainworks.com/support_thunderbird_win.php