This is a Facebook chat plugin for Pidgin and libpurple messengers. It connects to the new Facebook Chat IM service without the need for an API key.
Currently the plugin can log into the Facebook servers, grab the buddy list, send/receive messages, add/remove friends, receive notifications, search for Facebook friends and set your Facebook status.
Head over to the Google Code Repository Here
As you see there, there is also a windows version for you windows fans/users out there.
Download the Ubuntu .deb file and execute it to install, once installed, restart pidgin, then you will then click Accounts->Manage Accounts->Add->Facebook Chat
Enter your facebook email address
Then enter your password and click ok to connect!