first you should add imfeeds to your friend list in your IM program for example if you use Yahoo Messenger add imfeeds and if you are using Google Talk add imfeeds@gmail.com.
then type : join
that will give you a link, click it and begin using the service
adding feeds is possible by the site or this command :
sub
to unsubscribe from a feed type unsub
to get help type help in chat window
Source: http://bamdadi.com