using outlook 2007.

I created a rather large zip file of pictures (65M) that I attached to an email. The email is now in my outbox and Outlook keeps trying to send the email. I have tried to delete the email but I get a message that Outlook has started the sending process so it can't be deleted. Really would like to delete this but can't. Don't think this is causing a problem since it has been going on for the last couple of weeks. Sometimes I try to delete this and I get NO response.

How can I delete this file.

Thanks in advance