Pidgin already has support for a variety of messaging protocols, add to its chat-tacular arsenal with add-ons for Facebook and Twitter.
Over at Download Squad they've put together a step by step tutorial covering how to soup up Pidgin. We've previously covered the Pidgin Facebook plug-in, but integrating twitter updates is definitely a new-trick-on-the-block. The trick requires a gmail account so you can access the gTalk protocol in Pidgin as well as a plug-in for the twitter API. Check out the tutorial for detailed instructions and turn Pidgin into your mecca of messaging. For more customization ideas check out the ten must have plug-ins for Pidgin.