From http://superjared.com/entry/new-projects/#campfire_to_jabber
A proxy between Campfire and Jabber. Built in Ruby using Tinder and xmpp4r-simple to utilize Campfire and Jabber respectively. It also uses the "daemons" gem to spawn a long-running process. For each Campfire room in which you want to chat, you must also create a Jabber user, which was simple since I run my own Jabber server.
To install, first install the required gems:
sudo gem install tinder xmpp4r-simple daemons
Then place camper.rb in a place you don’t mind seeing .pid files, and configure it accordingly. Keep in mind that you can run several chats from the single configuration. Once configured, you should be able to start and stop the daemon:
ruby camper.rb start
ruby camper.rb stop