If you have recently changed the url of your page or site, and have placed a 301 redirect from the old url to the new url, do not be surprised if it takes a while for Google to recognize the change. Google says, "Finally, if your old URLs redirect to your new site using HTTP 301 (permanent) redirects, our crawler will know to use the new URL. Changes made in this way will take 6-8 weeks to be reflected in Google. "
You can find this information at www.google.com/remove.html, as well as much more information regarding removing information from the Google index.