Although we haven’t heard from Sony about this, it looks like the PS3 network is down for maintenance at the moment. I can personally confirm this, as I am unable to sign in at the moment.
We don’t have a solid time for when the network will be back up, but you’ll be able to keep updated on the situation by checking this Twitter update page on Google here. This page lists all the relevant results for the PSN Network, so you’ll be able to see the exact moment it goes live again.
Hopefully it won’t be too long until it is back up, as Sunday is always a good day for a Modern Warfare 2 session. If any of you know why the network is down, be sure to share it with us.
Alternatively, you can check out Sony’s official Twitter page here, for an update – although they have yet to post anything on this yet.