http://owlzyj4to3l5daq6edgsgp5z4lh4tzlnms4z6jv6xdtkily77j4b3byd.onion/beginner-guides/pidgin.html
If you're adding an existing account, then enter the password. Next, go to the Advanced tab. Here you can put a .onion address for the connect server. If you have a file transfer proxy as with Daniel's XMPP, you may enter it here. Finally, to route all traffic to and from your account over Tor, click on the Proxy tab.