The PerformancePoint Server 2007 Planning Data Migration Tool is now available on TechNet and the MS Download Center.

Norm Warren has provided some great additional guidance to support this here.

Documentation: http://technet.microsoft.com/en-us/library/cc512833.aspx

Download: http://www.microsoft.com/downloads/details.aspx?FamilyId=FA1C6CAD-45BD-4E5C-A257-4BBA84FA4224&displaylang=en