Exactly how should we use default wordpress text editor for my wordpress wordpress plugin.Any suggections please?

The WordPress Text editor is definitely an use of the TinyMCE Editor. You may use the files situated in wordpress_includes/js/tinymce and make a clear case of the editor by yourself, based on the documentation.

Take a look at this content for instance instructions:
http://my.opera.com/Contrid/blog/2007/04/28/wordpress-using-tinymce-with-your-plug-in http://www.keighl.com/2010/01/tinymce-in-wordpress-plugins/

and

http://wordpress.org/support/topic/how-i-can-use-tinymce-for-my-own-plugin