At yesterday's CR2.0 live webinar with Richard Byrne, some of the colleagues where asking for the possibility to embed a dropbox widget on their sites or blogs so their students could send their works without the need for passwords or usernames. I proposed box.net, but wasn't sure as how to get that widget. And today, after a few hours of research I came across the answer on this link http://blog.box.net/2009/03/04/box-upload-widget-create-a-file-drop...
, I haven't tried it just yet but knowing the job the guys from box.net are doing I'll put my hand in the fire for them.
Another option is the use of airdropper (http://secure.airdropper.com/
) for dropbox, this site allows to have files sent to your dropbox prior your request.
If I find any other I'll post a reply.