As you probably already know by the recent announcement, the monitoring and analytics components of PPS will merge into SharePoint 2010 next year and we will stop investigating in the planning module from PPS. PPS will receive one additional service pack (SP3) in the summer of 2009, with nothing planned beyond that.
It recently came to my attention (thanks to a partner) that the current Performance Management Specialization exam (70-556) will be replaced, because it is largely focused on the Budgeting, Planning, and Forecasting functionality within Performance Point Server. This exam is no longer relevant and will be replaced by a new, updated exam in the summer of 2009.
For more information see: https://partner.microsoft.com/global/program/competencies/msppbusinessintelligence/40043177