AppeInsider is reporting
that developers may receive their seeds of Mac OS X 10.5.5 as soon as this weekend, calling it a "maintenance and security update." They go on to say that the 10.5.5 Leopard update could provide support for those new notebooks
we've been hearing about.
Apple released their last update (10.5.4
) on June 30th. 10.5.4 included bug fixes and provided the framework for Apple's MobileMe webservice.