Upload file using a form

[eluser]überfuzz[/eluser]
I'm about to include, or write, a form that will allow users to send an email and attach a file(*.txt). How is this done, in a nice CI way..? My plan was something like this:

1. Upload the file using the uploading class.
2. Send info and attach the file using the mail class.

What would be the smoothest way of doing this in CI style?