This will highlight the second cell in the column. The color might now be the extact color you want though.
EDIT2: added the definition for testcell1, first,Second and Added Report as worksheet code
edit 3: changed <> to =
Sub runthis()
'Dim row As Integer
Dim TestCell As String
Dim first As String
Dim Second As String
Dim TestCell1 As String
Dim lastcell As Integer
Sheets("sheet1").Select
Dim Report As Worksheet
Set Report = Excel.Worksheets("Sheet1")
lastcell = Sheets("sheet1").Cells(Rows.Count, "A").End(xlUp).row
For row = 1 To lastcell
TestCell = "A" & CInt(row)
TestCell1 = "A" & (CInt(row) + 1)
first = Range(TestCell).Value
Second = Range(TestCell1).Value
If first = Second Then
Report.Cells(row, 1).Interior.ColorIndex = 3
End If
Next row
End Sub