On of my computer is old RHEL 5.1 on which I am not allowed to install pidgin. So I was trying to figure out how to create a bookmark button for GTalk gadget. Here is the solution. 
javascript:(function(){open('http://talkgadget.google.com/talkgadget/popout','_blank','width=300,height=445,toolbar=0,status=0,menubar=0,location=0,resizable=1,scrollbars=0')})();javascript:urchinTracker('/talk/outgoing/gadget')
Steps (Firefox):