Check out the download center for a great package that facilitates data import for PerformancePoint Planning.  It includes step by step directions on the recommended data import package steps in a typical PerformancePoint Planning Server application, a starter Visual Studio 2005 Business Intelligence Development Studio (BIDS) 2005 solution,  plus a SQL Server Integration Services (SSIS) project with two files which can be used as the starting point for Dimension and Fact data load packages.

In this sample, the Dimension data is set up to source from an Excel file, and the fact data package sources from a SQL Server database called CustomerDataScrubbed.  BizCorp is a sample Performance Point Planning application used as the destination. 

Make sure to read the starter instructions first, as it will explain how to use the templates,  including how and where to change your database connections, package variables and configuration file settings to make it work in your environment.