Didn't want to necrobump an old thread, so I started this one.
Seems ownCloud may be a viable open-source solution. Not only does it offer file syncing, but it allows multiple deployment options (Amazon, Google, server, etc), syncs images, bookmarks, and music. Granted, we don't need all of these features, but they are nice extras.
If we needed a hosted solution, owncube.com seems to offer more space (5GB vs 2GB) than dropbox.
Original Thread: Infrastructure for binary part of our project