I was searching about removing the a domain/site being listed in Web Search Results (like, Google Search) and i found solution, at here.
I believe it will be the solution but what i still need to know is:
It depends on how often your site is currently crawled by Google, the Google spider needs to re-read the robots.txt file before it can even consider removing your site from the SERPS
Google can take a day or a whole year depending on the amount of pages you have. On average for a 30 page site about 1-2months. They allow for some time increase its an error and not intended, and people don't lose their rankings.
If you want the Pages removed prompty then you should use Webmaster Tools and manually remove those pages using the URL removal tool and ensuring that it doesn't recrawl them by using metaname="robots" value="nofollow" and robots.txt
As already stated by Jack Locker, without any intervention this will depend upon when your site is recrawled and robots.txt re-read. How long it may take depends on your karma.
If it is is urgent to get the site out of the index, for example, if confidential information has been accidentally exposed and can be extracted from the index/cache, GWT has a number of different tools that let you speed up the process.
I won't go into specifics, since I do not now the particulars, but there are good tutorials about removal at Google Webmasters Central.
