Another method to get download url: When you start downloading the online installer, filename at end of url is msgr8in.exe
Change the url by putting a y in front of this filename i.e. ymsgr8in.exe keeping the rest of url same.
BTW URL for Yahoo! India Messenger 8.1 is: *us.dl1.yimg.com/download.yahoo.com/dl/msgr8/in/ymsgr8in.exe