Difference between SharePoint Foundation 2010 and SharePoint Server 2010:
SharePoint Foundation 2010 is free software by Microsoft to download and use without any purchase, and SharePoint Server 2010 is paid one licensed.SharePoint Foundation 2010 is base on which SharePoint Server 2010 is developed however SharePoint Server 2010 is having extra good features than SharePoint Foundation 2010 .
SharePoint Foundation 2010 doesnt have good exposure to Advanced Search functionality, MS Excel Spredsheet support, Visio diagrams, Info Path forms and security features whereas SharePoint 2010 does have all this and some other features too.
SharePoint 2010 Server = SharePoint Foundation 2010 + SharePoint 2010 Additional Features
