Take a look at
http://msdn2.microsoft.com/en-us/library/aa159891(office.11).aspx

Sample code that appears in that article is:

 Try
   xl.ScreenUpdating = False

   'Start with the Customers table
   dt = ds.Tables("Customers")

   'Add the column headings for the Customers
   Dim dc As DataColumn
   Dim iCols As Int32 = 0
   For Each dc In dt.Columns
     xl.Range("A1").Offset(0, iCols).Value = dc.ColumnName
     iCols += 1
   Next

   'Add the data
   Dim iRows As Int32
   For iRows = 0 To dt.Rows.Count - 1
     xl.Range("A2").Offset(iRows).Resize(1, iCols).Value = _
       dt.Rows(iRows).ItemArray()
   Next
 Catch ex As Exception