EmailNotifier is a add-on for nearly every E-Mail-client (like Outlook, Outlook Express, Pegasus). It adds a (optional: hidden) link to every outgoing message. As soon as the receiver open the message you will be informed. You will get information about date, time and IP-address of the read operation. The email-tracking works without approval or help of the receiver.
This software is a shareware. You will be able to download and test EmailNotifier during a certain period of time, then, if it does what you need, you will have to acquire the full version from EmailNotifier publisher. The EmailNotifier 1.7 free trial version contains an installer and an uninstaller, and has a size of 1678 Kilobytes.
For additional information and support request, please contact directly EmailNotifier publisher.

EmailNotifier Screenshot