I've been using Google Page Creator to move files back and forth, but it's kludgy and uploads are excruciatingly slow. I looked around a bit and found AOL's
Xdrive is now offering 5GB for free. It's PC centric, but I tried the browser applet with Camino and it was pretty efficient. Not quite drag and drop or webdav, but good enough.
I had an AOL screen name (my AOL username from 18 years ago is unavailable, AOL does not recyle screen names and there's no way to reclaim them) so I just used that. When I signed in I got a "service unavailable" message, but I just clicked for a while and eventually it let me in.
Upload was incredibly fast using their fancy uploader. I've never uploaded anything to the web that went so quickly.
Worth a try.