Apple has sent out a note to developers advising them that iTunes Connect, the back end interface for managing App Store apps, will be down for maintenance on Wednesday, July 13 from 9 a.m. to 4 p.m. PDT. They also warn that some countries will lose App Store access, and price changes might cause apps to temporarily become unavailable.
During this time, iTunes Connect will still be available. However, pricing changes made between 9 a.m. and 4 p.m. PDT will cause the app to become unavailable for purchase until maintenance is complete, at which point the app will become available at the new price. To avoid interruptions to the availability of your apps, do not make price changes during this time.
Lastly, customers may not be able to purchase apps in the Mexico, U.K., Australia, Switzerland, Japan or Norway storefronts during the scheduled maintenance.
Everything should be back to normal following the maintenance, and it's not difficult to imagine Apple's new OS X Lion launch for the Mac might be nicely set up soon thereafter.