How to integrate a chat application with other service like GTalk or Yahoo?

I have created a chat application using PHP, but it works only into my site(like the user need come to my site and chat..), i want that user can chat with me through any chat server like Gtalk,yahoo, or MSN. How ca开发者_JAVA技巧n it be done??

Try something like this

http://www.meebo.com/websites/

Or if you really want to code yet another chat room http://code.google.com/p/xmpphp/ will let you talk to jabber servers i.e Google talk