At the MS Excel team blog they have a great blog post where a member of the SQL Server Analysis Services team, Ashvini Sharma, will tell us about the PowerPivot.
The post gives a comprehensive look at the entire PowerPivot product, from front to back and names all components.
Read the entire article here: http://blogs.msdn.com/excel/archive/2009/10/22/introducing-powerpivot.aspx
The big question i have is, will the VertiPaq engine have an API where developers can build there own frontend on PowerPivot… with loading, connection and analysing sources in memory.