How do I create a global error handler?

[eluser]Unknown[/eluser]
I want to make sure that if there are any exceptions generated in my Code Igniter site, that the end user sees a "friendly" error page, but also, I want to capture the errors details and email them to myself.

For example, imagine my code tries to do a divide by zero, I want to capture that error message, mail it to me (the developer), and then finally, display a template that says to the end user "Oops, we're sorry but something bad happened."

How do I do this? I found the information about how to manually announce an error with show_error('message'), but I just want the framework to deal with any unhandled error in a global generic way.

Thank you,
Jon