Wonder no more! The updated SMS 2003 SP3 Supported Configurations document has been updated to reflect support for both Windows Vista SP1 and Windows Server 2008 clients. The Configuration Manager 2007 RTM supported configurations has also been updated to reflect support for these operating systems.
The latest SMS 2003 SP3 Supported Configurations document can be found online here: http://technet.microsoft.com/en-us/library/cc179956.aspx.
The latest Configuration Manager 2007 RTM Supported Configurations document can be found online here: http://technet.microsoft.com/en-us/library/cc161860.aspx.
Here's some more quick information about this update:
OK, so you've got SMS 2003 SP3 installed with Vista SP1 clients, but you can't narrow down package properties to only run on Vista SP1?
You need this hotfix: SMS 2003 with Service Pack 3 cannot deploy a package to client computers that are running Windows Vista with Service Pack 1.