If you have xl2k or higher:

Option Explicit
Sub testme01()
 
   Dim myNames() As String
   Dim fCtr As Long
   Dim myFile As String
   Dim myPath As String
   Dim RptWks As Worksheet
   Dim NewName As String
   Dim DestCell As Range
   
   'change the folder here
   myPath = "C:\my documents\excel\test"
   If myPath = "" Then Exit Sub
   If Right(myPath, 1) <> "\" Then
       myPath = myPath & "\"
   End If
   
   myFile = ""
   On Error Resume Next
   myFile = Dir(myPath & "*.xls")
   On Error GoTo 0
   If myFile = "" Then
       MsgBox "no files found"
       Exit Sub
   End If
   
   'get the list of files
   fCtr = 0
   Do While myFile <> ""
       fCtr = fCtr + 1
       ReDim Preserve myNames(1 To fCtr)
       myNames(fCtr) = myFile
       myFile = Dir()
   Loop

   If fCtr > 0 Then
       Set RptWks = Workbooks.Add(1).Worksheets(1)
       Set DestCell = RptWks.Range("a1")
       For fCtr = LBound(myNames) To UBound(myNames)
           DestCell.Value = myPath & myNames(fCtr)
           NewName = Replace(expression:=myNames(fCtr), _
               Find:=" (Inc).xls", _
               Replace:=" (Co).xls", _
               Start:=1, _
               Count:=-1, _
               compare:=vbTextCompare)
           If myNames(fCtr) = NewName Then
               DestCell.Offset(0, 1).Value = "Not renamed!"
               'skip it
           Else
               On Error Resume Next
               Name myPath & myNames(fCtr) As myPath & NewName
               If Err.Number <> 0 Then
                   DestCell.Offset(0, 1).Value = "Not renamed!"
               Else
                   DestCell.Offset(0, 1).Value = "renamed"
               End If
               Err.Clear
               On Error GoTo 0
           End If
           Set DestCell = DestCell.Offset(1, 0)
       Next fCtr
   End If
 
End Sub

If you're new to macros, you may want to read David McRitchie's intro at:
http://www.mvps.org/dmcritchie/excel/getstarted.htm