Currently we're having difficulties signing into the Network, and it appears that we are not alone.
Apparently Sony are aware of the issue and are currently working on a fix.
"We’re aware certain functions of PlayStation Network are down," claimed a post on the US PlayStation Blog. "We will report back here as soon as we can with more information.
"Thank you for your patience."
We currently have no idea when a fix will be coming, but we don't expect the service to be down for long.