Currently, we have no support for bound datasources in our WPF grid. Support for simple flat datasources will be available in our Volume 1 2009 (Jan time frame) release. At that point, sorting support should be available for datasources that inherently support sorting.
Support for filtering and sorting of arbitary datasources will come in later releases next year.
That said, it is possible to use the virtual mode of our GridControl along with our Grouping Engine to sort and filter things now. This support is not the built-in support that will come later, and the simple API that is exposed through the helper class will be different when we offer our built-in support. Here is a link to a sample that has a helper class that will let you sort and filter using our GroupingEngine and display the results in a WPF GridControl.
http://www.syncfusion.com/support/user/uploads/GroupingSample_6cbf8e88.zip