Drag and drop AJAX multiple file uploader

Hi,

I recently came across this post: 

http://www.aspsnippets.com/Articles/Multiple-File-Uploads-Gmail-Style-using-JQuery-and-ASP.Net.aspx

I've been using this setup for a while and it works great, however I'd like to integrate a drag and drop system into this so the user can just drag files into the browser window and have them upload that way. Does anyone know how to go about doing this?

Thanks in advance :)

-Mike