Opensource email script to view email attachments?

[wscreate]

I have learned to build a script that will send email attachments via PHP. That was awesome and I am still excited about it. Now, I am trying to build a script that will display emails and attachments just like most web mail programs do. I have found some documentation on the subject, but what I am really looking for is a working, opensource script which I can view and study so I can see how it all fits and why. That is how I learn best.

Do you know of any such, functioning, open source script? If so, please point the way so my learning can continue.

Thanks