In an attempt to get the guide service stable again, all xmltv files have been removed. The MCEGuide client was also removed and new users will currently be unable to make use of MCEGuide.
If you already downloaded the client, you can install it and try downloading the guide at a later time. If you haven't downloaded the client yet, then I'm afraid you will be left in the dark till the guide service is stable again.
Regards
[Update : The MCEGuide client is available for download again]