The Ubuntu One service is closing and being open sourced:
Additionally, we continue to believe in the Ubuntu One file services, the quality of the code, and the user experience, so will release the code as open source software to give others an opportunity to build on this code to create an open source file syncing platform.
How can I self-host the server and set up my Ubuntu One clients to use this server?
I looked at the Launchpad project site, but it seems that all the server-side code is still hidden.