If you want to be annoyed into a screaming stupor whenever you get a message on your computer, get an iKnock. If you'd rather have something more, shall we say—subtle to let you know when a new email comes in, then this USB-powered mailbox is a better choice. Connected to your Webmail client, it emits a gentle glow to let you know you've got one waiting.
The USB Webmail Notifier connects to your private email account and lets you know with just a glance at your desk if you have mail, and how many new ones you've got waiting by lighting up blue, green or red.
It supports Gmail, Yahoo Mailplus!, Outlook, Outlook Express, and ISP with available pOP3 service.