Edit: PlayStation Store will not be returning tomorrow, PlayStation blog manager James Gallagher has confirmed:

The latest information I have on PlayStation Store is that we are aiming to have it live by the end of May. Contrary to popular rumours, it will not be reopening tomorrow but we will let you know here as soon as the date is confirmed.

Original story:

PlayStation Network services have been online for a little while now, but the PlayStation Store is still missing in action. It might not be gone for much longer though, as rumours point to restoration later today.

In Europe, PSN will be down for maintenance from 4pm to 12am UK time. While PSN maintenance is a regular occurrence, it's rarely scheduled for such a busy time nor for so long.

Previous rumours suggested developers had been told the store would return today, but this now seems unlikely.

When the Store does return, Sony will be offering two updates per week in order to catch up with weeks missed, which should mean we finally get to play Under Siege.

We'll keep you updated.

[source ie.playstation.com]