From Robert Bowlings twitter page (Infinity Wards head geek)

1. Xbox Live servers are maintained and ran by Microsoft. PSN servers are ran and maintained by 3rd party companies hired to do so.

2. It's related to the servers being down at the moment during an upgrade. It'll be fixed when the servers come back up.

3. MP doesn't require a patch. It's a server overload not a bug in the code. They're working to have servers back up ASAP

meh......

656,000 copies sold since Mon... and that's just in the UK... Talk about traffic....