The ConfigMgr homepage may not be up to date yet but here is the direct download link to download SP1: http://www.microsoft.com/downloads/details.aspx?FamilyId=5AAE62E8-4B7F-4AF7-BE01-AEFAA4BF059A&displaylang=en
This release (among the usual bug fixes) brings forward these new features:
1. More complete support for management of Windows Vista SP1 (Vista SP1)and Windows Server 2008 (Server 2008).
2. Support for SCCM 2007 Server Site roles on Server 2008.
3. Out of band and in band management of Intel AMT devices.
4. Asset Intelligence 1.5 which is our first release with a connection back to System Center Online for regular updates to the Asset catalog