Messenger In Java?

Hello Everyone,
This is my first ever post on this forum.
I am about to develop a messenger application in Java(like MSN, Yahoo).
I want to know that if any of you people have developed such application?
If so then how should should I go about developing this type of application using socket programming. What strategy should I follow.
This is my first ever socket programming application.
Previously I've worked on Servlets,Java Bean, JSP.
I would greatly appreciate your help.

Nouman,
Before you get going, be sure to check out Jabber at http://www.jabber.org . It's an open standard for messaging that includes a gateway architecture that allows you to talk to different IM services.
You should find links to tons of source code for the clients and servers, many written in Java.
Best of luck!
-Joel

Continuing from Joel's suggestion (it's the route I went when my former employer was going to do a similar internal project), take a look at Jabberbeans, which is a pretty decent framework for working with the Jabber clients. I found it was actually fairly easy to get a basic client up and running quickly using these...