I've been looking at and playing with the Data Mining Add-in for Excel for the past month to see how scientists could utilize it in analyzing their data - and I think it will be quite useful.  The idea behind it is to send data in an Excel table to a SQL Server Analysis Server and let it execute it's algorithms over it - it's great for finding outliers as well as seeing the relationship of data...can't wait for it to be fully released...

Data Mining Add-ins For Office 2007 In The Works

Attendees at TechEd 2006 got a first look of the SQL Server Data Mining Add-ins for Office 2007, which garnered a spot on the Top Ten TechEd Hot Buttons. The release will include Table Analysis Tools for Excel, Data Mining Client for Excel and Data Mining Templates for Visio. Watch this space for more news on the add-ins, coming soon to your desktop in beta form with Community Technology Preview 2 (CTP2) of SQL Server 2005 Service Pack 2 (SP2) in October. In the meantime, you can check out some early screenshots. You'll also have an opportunity to see the add-ins live at PASS 2006.

Source: The Data Miner: SQL Server Data Mining News