Sorry for such late reply.
My application is a simple web app with servlets and jsp's in it.
I am using Jboss 6.2 EAP as application server and IIS 7 for web server.
All my requests are routed through the IIS server using Application Request Routing.
So can you please let me know if i can load balance 2 jboss instances running on same machine on different port.
If you run a web application you need to have a loadbalancing in front of JBoss. There is no difference whether you run the instances on the same or different machines.
You should start with this documentation High Availability Guide