Here is one i made earlier, for a similiar question asked in the VB forums only a few weeks ago;
Private Sub doSomething()
Dim xlApp As Microsoft.Office.Interop.Excel.Application = New Microsoft.Office.Interop.Excel.Application()
Dim xlWk As Microsoft.Office.Interop.Excel.Workbook = xlApp.Workbooks.Add()
Dim xlSheet As Microsoft.Office.Interop.Excel.Worksheet = xlWk.Worksheets(1)
xlApp.Visible = True
xlSheet.Range("A1").Value = "Some Text Value on 1 line"
xlSheet.Range("A5").Value = "Some text value on" + vbCrLf + "2 lines"
xlSheet.Columns().AutoFit()
xlSheet.Rows().AutoFit()
xlSheet.Range("B10").Value = "Some text aligned to the center"
xlSheet.Range("B10").ColumnWidth = 120
xlSheet.Range("B10").CurrentRegion.HorizontalAlignment = Microsoft.Office.Interop.Excel.Constants.xlCenter
End Sub
NOTE: there are other HorizontalAlignment constants available in the object model,e.g.
HorizontalAlignment.Left (.Right) (.Center)
but these do not work, you must use the one shown above.