Well.....finally i have worked out how to post cross-domain data which is restricted by browser's security policies. What is it?? This will be used for posting AJAX requests via java-script to any web-service or web-page in any DOMAIN and also get back the results from there.
JSONP allows you to call a URL outside of the domain the script is running from with a callback. This callback lives in the calling script so, technically, it never leaves that scope. There's lots of other resources out there to help you implement it in your own code including jQuery and Prototype JSON handling.