How to save Uploaded image in custom option panel?

I’m trying to add a custom option panel to a new template following a tutorial found on NetTuts. I saved all the code for the option panel inside a file called optionpanel.php (LoL) and everything is working but now I would like to add an Upload/Image button so I’ll be able to change images inside a slideshow straight from WordPress Media Library instead of connecting via FTP each time.