If you are experiencing any difficulty getting on various Google Apps it's because Google is having issues right now nationwide. Be patient; the services should be back up soon. You will see various services restored as you continue to refresh.
UPDATE: Google appears to be up for some users.
UPDATE 2: Gmail, Google+, and Talk seem to be running fine. Google is going to continue to investigate as to why this happened. Keep up with TechRaptor to get the latest info.