A) First, jailbreak your iTouch.
B) After the jailbreak,the Cydia icon should appear on your iTouch home screen.
C) Download and install OSCall client software through Cydia following the steps listed in the manual.The "OSCall"client icon should now appear on your iTouch home screen.
D) Start the OSCall client after making a pair with your OSCall bluetooth.
Jailbreak method:
http://www.idownloadblog.com/jailbreak/
http://www.iphonehacks.com/jailbreak_iphone