The following is their service status update that appears when you currently log into. Mac, which outlines the MobileMe launch on July 9th. 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.
It is also anticipated that the new version of iTunes will most likely be showing up around this time). MobileMe costs $99/year in the U.S., but will be available for $69 with the purchase of an iPhone 3G on July 11th.