Sudakar

Websphere is name of the brand which has multiple products in it. I think, you would like to learn websphere application server.

The best resources to start are :
IBM redbooks
IBM education assistant web site
WebSphere step-by-step book
packt IBM websphere administration book.

We suggest you to start reading and understanding the concepts and then download a 90days trail software and you can test your leanings. If you encounter any issues while doing so, you are always welcome to post a questions for us in the forums.

Thanks
Joseph