The Facebook chat application is a very nice tool for communicating with friends without using any external chat software. But using facebook chat in the main interface is a problem due to multiple distractions etc.
To access the chat app. from Facebook without any other information such as bulletin board, messages and all other services offered by social network, you can use a direct link to chat only to see your friends.
Chat With Multiple Facebook Friends Easily
By logging in to exclusively chat with multiple Facebook friends, you can communicate with the contacts in a manner similar to MSN.