Commerce and Marketplaces will be affected for about an hour.

Sony Online Entertainment will be performing maintenance beginning at 7:00 AM Pacific on January 25, 2012. This will impact the following services:

• Account management will be unavailable starting at 7:00 AM to approximately 8:00 AM Pacific.
• Commerce transactions, including purchases on SOE websites and in-game marketplaces will be unavailable between 7:00 AM to approximately 8:00 AM Pacific.
• Forums will remain open during the downtime however you may lose permissions and experience occasional disconnects between 7:00 AM to approximately 8:00 AM Pacific.
• Logins for PoxNora®, Star Wars®: Clone Wars Adventures™ and Free Realms® will be affected from 7:00 AM to approximately 8:00 AM Pacific.

Here's our handy Time Zone Conversion tool to help you plan! 

Source:  Station forums