Private Sub Worksheet_SelectionChange(ByVal Target As Excel.Range)
Static OldCell As Range
If Not OldCell Is Nothing Then
OldCell.Interior.ColorIndex = xlColorIndexNone
End If
Target.Interior.ColorIndex = 6 'yellow
Set OldCell = Target
End Sub

http://www.excelforum.com/excel-new-users/487299-change-highlight-color-on-active-cells.html

Use this code to change the default highlight color for a cell in excel 2007.   Right click on the sheet name and click view code,  Paste this code into the module that comes up.

Change Highlight Color Excel 2007

excel, color

Visual Basic