Xceed WPF DataGrid - For Free!
WPF didn’t ship with a DataGrid control in .NET Framework 3.0. The guys at Xceed Software recognized that and have now released an enterprise strength WPF DataGrid control to the community.
There is a beautiful demo XBAP called Xceed DataGrid for WPF LiveExplorer that lets you see the control in action and use it for yourself.
Get the Xceed DataGrid control. [Requires .NET Framework 3.0 or Windows Vista]