Mail problem

I am having a problem with email. Last week, I tried to send a bunch of photos as attachments to an email, about 25 megs worth. The upload speed was very slow, as I have 6mb ADSL limited to 768K upload speed. I decided to cancel the sending of the email, and afterward, I removed the message from the outbox folder so as to prevent it from being sent again. The problem is, every time I restart the mail program, it tries to send this same email again, though it is not present in the outbox. If you look at the activity panel of the mail program, it shows it is sending that same email, and, my downstream speed drops to next to nothing. How do I clear whatever que is still present for sending this email?

Thanks!