Apple is about to turn the switch on its MobileMe service. In preparation, it will take .Mac offline at 9 PM EDT tomorrow night, Wednesday, July 9. According to the announcement:

“Members will be unable to access www.mac.com or any .Mac services during this time with the exception of .Mac Mail accessed via a desktop application, iPhone, or iPod touch. MobileMe will be available as soon as possible during this maintenance window.”

Complete information on the switch can be found on Apple’s .Mac to MobileMe Transition FAQ.