PuSH Bot
Note: Google App Engine deprecated XMPP support in 2016, and removed it on 2017. This project is archived and the serivce is no longer operational. The information below and the code are archived.
PuSH Bot lets you receive notifications via XMPP of updates to feeds that support PubSubHubbub (commonly abbreviated to PuSH). This means that you can receive updates from Blogger, TypePad, Movable Type and LiveJournal blogs, any FeedBurner feed and many other sources to Google Talk or any other Jabber/XMPP account.
It is running at push-bot.appspot.com.