As Apple prepares for the much-anticipated launch of the iPhone 3G, the company said it will roll out its MobileMe wireless syncing and online storage service sometime Wednesday evening.

"As part of the MobileMe launch, www.mac.com will be taken offline at 6 p.m. PT on Wednesday, July 9th," read a message on the company's Web site. "MobileMe will be available as soon as possible during this maintenance window."

Introduced at Apple's WWDC conference last month, MobileMe is a cloud storage service that will enable push e-mail and real-time synchronization of contacts, calendar items, and other information between multiple devices without a need for a Microsoft exchange server.

"Think of MobileMe as Exchange for the rest of us," said Phil Shiller, Apple's senior VP of worldwide product marketing, during a presentation.

The service will work with the iPhone's calendar, contacts, and mail applications in addition to working with Mail, iCal, and Address Book on the Macintosh and Outlook on Windows. Users will be able manage their accounts through Me.com from any Web-connected device.

Users will also be able to use MobileMe to store and share photos, videos and other data wirelessly. MobileMe will be replacing the existing .Mac data storage and syncing service, and the company said existing members will automatically be transferred to the new service.

During the scheduled maintenance, .Mac members will not have access to services except for .Mac Mail accessed from an iPod touch, iPhone or desktop application.

A one-year subscription to MobileMe will cost $99 for 20 GB of storage, and users can purchase additional storage.