GTalk Contact Notifications For Chrome

GTalk Contact Notifications is a Chrome extension which gives Gtalk alerts like when some one has logged in & is available for chat or has commented.You need to be in Gmail for this feature to work.Although the extension works for both Google App as well as Gmail,there must be one Gmail tab in the browser.So now if someone log-ins you will get a chrome alert.The extension also comes with features where you can customize how long the notification screen must last etc in the extensions settings.And incase you don't have gtalk installed,this might be a better suitable alternative.
Download it from here