g1smd - 3:37 pm on Oct 27, 2005 (gmt 0)
If Google ever sees a link to a page (even if that page doesn't actually exist, and has never existed, and never will exist) then it will still show the URL that it has found as a URL-only entry in the SERPs. Listing that URL in your robots.txt will stop the URL from being crawled and indexed. It will NOT stop the URL from being listed as a URL-only entry for ever more though. Only a noindex meta tag on the page itself can stop the URL from appearing at all.