Here’s the official announcement from http://www.microsoft.com/bi/partners/default.aspx :

Financial Planning Accelerator

Microsoft is pleased to make available the Financial Planning Accelerator (FPA). The FPA is source code and project files derived from the PerformancePoint Server 2007 Planning module. Based on requests from customers and partners, we are making this code available on a no-cost, individual license.
This is unsupported source code that customers and partners can use to support or change PerformancePoint Server Planning functionality. Derived object code files can be distributed to end users with Microsoft SharePoint Server Enterprise Client Access Licenses. To obtain access to the FPA a license agreement between Microsoft and the customer or partner is required. After that agreement is in place, download instructions will be made available.
Please e-mail fpasupp@microsoft.com to request the agreement.

It’s not exactly open source, but it does mean that the partners who were hit hardest when PerformancePoint Planning was killed off can now get their hands on the source code, modify it and sell it on to their customers so long as those customers have the right Sharepoint licences. The question is now, will anyone take Microsoft up on this offer?