PushMail is a nice, reasonably priced (2.49 euro, so I guess that's about $2.99) iPhone application that is intended to realize push mail notifications (see update of my GPush post). It does so by giving you an @dopushmail.com e-mail address. Any e-mail sent or forwarded to that address will not be stored, but rather pushed to your iPhone. Any mail you send to it.
echo | mail -s "$*" email@example.com
chmod'ed it +x so I could execute it. Now, I can run it like this:
push-notify This is a test
And "This is a test" will appear on your iPhone. Of course, this has many applications. If you have a long batch job or compilation running and want to know when it has finished executing, you just run the command like this:
make; push-notify Done with compilation
and you'll get a notification when it's done. With some notification you could probably also receive a notification when something went wrong, when a server reported some exception. As long as you can invoke the push-notify script when it happens, you'll be notified within seconds.