Officially only for MS Premier support (48 hours prior to worldwide release) but everyone can get it NOW.
With the introduction of Systems Management Server 2.0 Service Pack 5 (SMS 2.0 SP5), Microsoft continues to sustain and enhance the capabilities of SMS 2.0. For an overview of several key improvements, refer to List of Fixes in Systems Management Server 2.0 Service Pack 5 (Q816549) in the Knowledge Base on the Microsoft Product Support Services site.