Having connection to Latest Yahoo Messenger Protocol in C#

I want to program a simple GUI to connect to Yahoo! Protocol and act as a messengers which use them now. So, could any one describe Yahoo! Protocol structure ( Please help me in using of latest version of this 开发者_如何转开发protocol ).

Thanks about your attention.

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I think you will find these links helpful as they describe several aspects the Yahoo! Protocol...

http://sourceforge.net/projects/ycs/
http://www.ycoderscookbook.com/
http://www.codeproject.com/KB/vb/YCC_Trainer.aspx
Yahoo Messenger Library C#
http://www.carbonize.co.uk/ymsg16.html
http://libyahoo2.sourceforge.net/
http://www.venkydude.com/articles/yahoo.htm

some general information http://en.wikipedia.org/wiki/Yahoo!_Messenger_Protocol