The PlayStation Network will have a maintenance period on Tuesday, May 24, lasting about two hours. Maintenance will begin at 9:30 pm PST, and end at 11:30 pm PST, or from 12:30 am EST to 2:30 am EST, for those of us on the east coast.
During maintenance players will not be able to access PlayStation Store, Video, or account management. However, signing in ahead of time will grant access to "most" applications.
"We strive to ensure that PlayStation Network services are available at all times, but occasionally we must take PlayStation Network offline to perform essential maintenance and implement feature enhancements. We are working hard to reduce the duration of each maintenance"
The PSN Service Status page should tell you what will be happening and when, if you'd like on-the-fly updates.
