SendMail is really an excellent email program found on most Unix systems. I just borrowed the name for my tutorial on sending email programmatically from an Android phone.
Long ago, when I worked on the Palm OS, one could create an email message programmatically, and then place it in the Outbox of the Email application. Once the PDA was synced with the PC, the email would be sent. I was looking for a similar way to send email from the Android phone. After searching the google groups and scouring websites and android docs, I managed to piece together a simple example.