The PlayStation Network is scheduled for maintenance starting tomorrow, July 26, at 8am Pacific Standard Time, according to the American PlayStation Network Support page.
This maintenance is set to last roughly until 11:00pm PST. The post also stated that users who have logged into the PlayStation Network since July 21 will still be able to use applications like Netflix and Hulu, as well as play online games normally. The only hindrances that may occur are when accessing the PlayStation Store or PlayStation Home, where users may be greeted with a prompt, "PlayStation Network is undergoing maintenance."
Other than the PS Store and PS Home, everything else should run normally. If anyone experiences anything differently than what was described above, let us know and we’ll look into it.