From Comm-Unity Networking Systems:
MMEmail is a user-friendly send email plug-in for FileMaker Pro 7 and later. It is different than other email plug-ins in the sense that it does most of the work for both the end-user and the developer.
MMEmail has a built-in email window which allows the end-user to compose an email message as if they were using a normal email client. From within the email window, you can set the To, Subject, and Body, as well as Attach files. You can use a special Auto-enter Hierarchal Menu of predefined email addresses to populate the To field. The Subject and Body of your message can contain Merge Fields to grab information from the current record before sending the message. Merge Fields can be inserted easily with a Contextual Menu. You can select Attachments via a file dialog as well as selecting Container Fields from a menu. When you click the Send button, the email window can automatically send the message, or store entered values for use with a non-window email function.