YOu can do it with formulas or with a macro. For the latter, John Walkenbach's
Power Utility Pak has this ability. Otherwise, the following macro will
operate on the cells that are selected at the time you run it.
Sub ChangeCase()
Dim Cell As Range
On Error Goto ErrTrap
For Each Cell in Selection.SpecialCells(xlCellTypeConstants, xlTextValues)
Cell.Value = UCase$(Cell.Value)
Next Cell
Done:
Exit Sub
ErrTrap:
Resume Done
End Sub