We actually have that already :)

At one we had it announced on the page, but then people complained that they couldn't do it in their browser - because they used one that didn't support it. We'll probably put it back in somehow. We'll think about it.

I've used script.aculo.us and had it work in Safari, Firefox, and Google Chrome; christopherwoodall.com/youtube.

JQuery also has a Drag-and-Drop feature.

Only one missing... Those were the users complaining.

You need to fallback into regular file select if the browser doesn't support it. :)