The best way would be to wait for Windows. At that time, I would back up any files I wanted to keep, music, pictures, etc... Install Windows and let it wipe out Ubuntu. Once Windows is up and running, then reinstall Ubuntu either as standard dual boot, or install it inside Windows using the WUBI installer.
This installs Ubuntu just like any other Windows program and if you decide to remove it, you simply go to the Windows Control Panel and tell it to remove it the same way you would any other Windows program. Works very well.