The thing about internet-rumors is they are very often wrong. For instance, the rumor that we reported last week, that said the PlayStation Store was going to be open on the 24th. Much like reports of the end of the world, it didn't happen, and it looks like it's not going to happen today.
Instead of the return of the PSN Store, you'll get some limited lack of functions between now and approximately 5pm Pacific. The majority of PSN users should still be able to play online, but Registration and Account Management will be inaccessible, including the password reset process.
Here's the official quote from Sony on when the PlayStation Store will come back:
"For those asking about the PlayStation Store, we’re still targeting restoration of all services by the end of this month. Contrary to reports, the Store will not be publishing today."
Source: PlayStation Blog