even though i have a hunch that i know what you're talking about, i have written a multiple file upload script (source is on the page as a link, too) here: http://www.fandelem.com/uploads/
now then, if you are referring to being able to select multiple files via the ctrl/shift key in the dialog box (after you click on 'browse') .. php cannot do this .. you need to write a java applet (v. extensive 🙂
cheers,
kyle