How can I automate sending mail using a script?

I have in the past heard of using nail for this task, but I can't seem to find it for my distribution (Ubuntu 11.04) in any of the repositories. What program can I use to one-off emails from a shell like so: send-mail -to me@email.com -file attachment.zip -message "Hello World" Is there a program out there through which I can script mail sending as above?