From where can I download Ubuntu SDK for mobile application development? I can not find any links.
The installation instructions for the Ubuntu SDK can be found at the Ubuntu App Developer Site. The guide currently only supports Ubuntu as the installation host, but since the SDK is based on Qt5 and QtQuick 2.0 you should be able to port (integrate) it yourself to other platforms after installing Qt5 (see the Qt5 Download Page).
The problem is that you won't be able to test the full functionality of your applications yet, as on the desktop you'll need to run the them using Qt's QML viewer (
There might be an emulator in the future, but it isn't clear yet when it will be released and if there will be a Windows version of it.
So I think the best solutions for you are:
(I would prefer the third point!)