Michel I think he is saying that he not even own the Web application, if I understood correctly he wanted to redirect the user from his application to for example hotmail and do an auto sign in in hotmail so the user didn't had to logon again, did I understood correctly Riyaz?
If so then the answer is no, once you redirect to the other site is out of your control you can't run any more code unless that other site was build by you also or a partner of your's where you can pass parameters on the query string and the other web app reads it and process them, other then that you can't run any code from your web app on another web app/site.

>>do you think it is acheivable in J# ?
>
>It should be. All those environments should be able to read the browser information such as cookies.