Howard Email Notifier is described as 'Howard is a replacement for the Windows Live Messenger email notification. A tooltip and a sound will notify you about a new email. The tooltip shows you the sender and email subject. Just click the tooltip or icon to open your inbox in your browser or Windows Mail'. There are nine alternatives to Howard Email Notifier for a variety of platforms, including Windows, Linux, Firefox, Mac and Google Chrome. The best alternative is POP Peeper, which is free. Other great apps like Howard Email Notifier are Checker Plus for Gmail (Free), Magic Mail Monitor (MMM) (Free), Google Mail Checker (Free) and Panel & Notifier for Gmail™ (Free).
POP Peeper is an email notifier that runs in your Windows task bar and alerts you when you have new email on your POP3, IMAP (with IDLE support), Hotmail\MSN\LiveMail, Yahoo, GMail, Mail.com, MyWay, Excite, iWon, Lycos.com, RediffMail, Juno and NetZero accounts.
Displays new emails, sender's contact photo, and notifications, and allows the user to listen, read or delete emails without opening Gmail! Supports multiple accounts plus and provides many other tools.
Magic Mail Monitor (MMM) is a free POP3 mail monitor with multiple accounts support. It sits silently in your system tray, and notifies you about new messages in your mailboxes. Then you can preview messages and delete unwanted mail in order to avoid spam and viruses.
Mailnag is a daemon program that checks POP3 and IMAP servers for new mail. On mail arrival it performs various actions provided by plugins. Mailnag comes with a set of desktop-independent default plugins for visual/sound notifications, script execution etc.