MacRumors.com

Apple has seeded a second version of Mac OS X 10.5.4 to developers today. While the latest build (9e12) fixes a dozen more issues in Mac OS X Leopard, the biggest new feature to be supported will be Apple's recently announced MobileMe service. MobileMe is Apple's .Mac replacement service which will allow users to sync contacts, email, and calendar across various devices. It also provides advanced web applications to access your information anywhere with a web browser.

Apple has announced that MobileMe will be launched in early July. Apple's system requirements for MobileMe include Mac OS X 10.5.4 as well as iTunes 7.7, so we expect these two updates to also be released in early July.

Apple provides a Frequently Asked Questions document for existing .Mac customers who will be transitioning to MobileMe.

Update: The system requirements for MobileMe also list 10.4.11 as being compatible, but "some features require Mac OS X v10.5 and iLife ’08."