How do I create a cluster and perform a task using it. An example will be handy. Also any suitable links regarding clusters are welcome.

The only clustering software I have successfully setup is a Mosix cluster. Homepage is www.mosix.org. The nice thing about Mosix is that once the cluster is going you don't have to do anything special. If one machine is heavily loaded Mosix will aitomatically migrate some processes to a different machine. This is all done automatically. I would recommend reading as much info as you can first to make sure it will be useful in your situation. Mosix will take some time to setup but it is not insanely hard to do. You basically: download a kernel patch - apply patch to kernel - re-compile kernel - edit config file - reboot - repeat for all cluster machines.
I'm sure there are other cluster options out there but I think Mosix is at least worth a look.

thanks for providing useful links.

I set up a rocks cluster last month. Think it works... not sure how to test it. Go to http://rocks.npaci.edu and follow the instructions. It was the only one that worked for me. Whatever you do, do not try to use the book "Building Linux Clusters" by O'Reilly. It has so many errors in it that it was pulled from the shelves.

If you discover how to test the system, i.e. 1. what speed is the cluster and 2. how do you set up a program (with an example), please let me know through the forum. thx..