The PSN will be offline due to a scheduled maintenance later on today.

On the PlayStation Blog, Sony has announced that the PlayStation Network will undergo maintenance from 8 am (Jan 19) until 9pm PST.

During this period, you will not be able to access the following:

• PlayStation Store on PS3, PSP, and Media Go.
• PlayStation Network Account Management.
• PlayStation Network Account Registration.
• PlayStation Home
• Music Unlimited & Video Unlimited services

In terms of multiplayer gaming, if you’re online “before the start of the maintenance”, then you should be able to stay on to play online. However, if you try to sign in after the maintenance starts, you “may be presented with the site maintenance notification page if [you] haven’t signed in recently.” Any trophies you earn during the maintenance will be saved, and once the PSN is back up, your PSN ID will be updated.