>does anyone knows Yahoo Messenger Automation with VFP, if so please give me hints

As far as I know, there is no API avail for Yahoo Messenger, but there are other things you can do. You could make your own Yahoo client for example. There is this http://sourceforge.net/projects/libyahoo2/ which is written in C that might help, and you can also take a look at this.. http://www.codeproject.com/internet/mcapi.asp
Hope this helps.