POP Peeper is a free and small application that runs in the windows taskbar and alerts you when a new mail arrives in your email accounts. It can alert you visually or audibly when a new mail arrives in your POP 3 or IMAP accounts. It supports a large number of web mail email providers like Gmail, Hotmail, Rediffmail, Yahoo etc.

After you have configured it with your accounts, it will monitor your mail regularly and will inform you when a new mail comes. You can get video as well as audio alerts like flashing scroll lock LED, audio sound, screensaver etc. You can configure a different sound with different email accounts. You can even use it to read email with html support and can also be used to send emails to contacts on your address book. It can also work with file attachments and can also save and open them. You can also password protect it with a password so that only you can view your messages. You can configure it as many accounts as you want, there is no limit. You can also specify intervals when each accounts will get checked.

It does not provide any spam filtering but if you are looking for a notification program, this one is good. It works on almost all the version of windows.