But, one of the disadvantages of UltraSurf is that, when browsing with Firefox browser it does not change your IP address automatically, instead you need to change the settings manually. Now it is possible with this Firefox add-on.
How to use it?
First of all download (442Kb) and install UltraSurf software from here (No installation required, just double click the exe file when needed). Then download (23Kb) Ultrasurf Firefox add-on and unzip it.
Open Firefox browser and drag the wjbutton_en.xpi file to Firefox window. Click the "Install" button to install it.
The UltraSurf icon / text will show at the right-bottom of the Firefox window. Close all Firefox windows and re-open Firefox.
To uninstall the add-on, go to tools - add-ons of Firefox and uninstall it.