Brendan Tompkins  has written a handy utility that can transform an ADO.NET DataSet into different formats, including ADO Recordset XML, Comma Delimited, Tab Delimited and Excel XML. He writes about it in his post Transform an ADO.NET DataSet to ADO Recordset XML, Excel XML and more!  . Below is an excerpt from his blog posting

To use this, simply make the method call like so:

Util.ExportUtils.ExportDataSet(this.exampleDataSet1, "ADOXMLExport", 
       Common.DataSetExportType.ADORecordSet,
       this.Context);

Notice that the third parameter is an enumeration specifying the export type. This enum looks like this:

public enum DataSetExportType
{
   XML,
   ExcelXML,
   TabDelimited,
   CommaDelimited,
   ADORecordSet
}

Why would anyone want to go from ADO.NET DataSet to an ADO Recordset?  Well, one big reason is to funnel  a .NET DataSet's data into an Office Web Component, such as a PivotTable and PivotChart. 

That's power of exchanging data using XML. Even if the underlying data structures or platforms are different, interoperability is just an XSLT transformation away.