Sony has announced on its European forums
that maintenance time has been scheduled for the PlayStation Network this Thursday, February 2, from 2PM GMT until 8AM Friday morning. If the maintenance carries over to the US (and it usually does), it'll start at 6AM PST Thursday until midnight PST, or 9AM to 3AM for those of you on the East Coast.
Fortunately, the outage doesn't seem to include gameplay -- Sony says that it will only affect the PS Store, Customer Account Management and Registration services. PlayStation Home, however, will be offline the entire time. So ... that doesn't sound so bad! Just pour yourself a cup of tea, grab something good to read and wrap yourself in a warm blanket, and the outage will be over before you know it.