NOTE: This is an old post from 2009 talking about PowerPivot v1 CTP3. If you are looking for PowerPivot v2 CTP3 (and OF COURSE YOU ARE!), please see this post instead:
Old post follows:
OK folks, everything is available as of today! Here is a collection of the links you will need to grab PowerPivot and try it out:)
Office 2010 Beta 2
You must have the most recent Beta of Excel 2010 installed prior to installing the PowerPivot addin.
Note: Install 64-bit if you intend to use large data volumes.
PowerPivot for Excel 2010
This is the addin required to design PowerPivot models and reports in Excel 2010.
Note: the addin must match the architecture of the Office build installed – 32- or 64-bit
(Once you have Excel 2010 and the addin installed, you are good to go. You don’t need to install SharePoint or the SharePoint addin below until you are ready to try out the server story.)
SharePoint 2010 Beta 2
PowerPivot for SharePoint 2010
This is the SharePoint addin that allows you to publish, share, and manage PowerPivot reports. Requires SharePoint 2010 Beta 2, above.
On both sites, expand Servers, then look for SQL Server 2008 R2 – that contains the PowerPivot SharePoint addin.