ISLIKE

Returns whether a particular string matches a certain pattern.
For instructions on how to add a function to a workbook refer to the page under Inserting Functions

'sText - The text you want to test.
'sPattern - The pattern you want to check.

Public Function ISLIKE(ByVal sText As String, _ 
                       ByVal sPattern As String) As Boolean 

   If sText Like sPattern Then 
      ISLIKE = True 
   Else 
      ISLIKE = False 
   End If 
End Function 

You can use the built-in COUNTIF function to achieve the same thing.
You cannot use the [] operator in your patterns if you use the COUNTIF function.