PatternColorIndex Property [Excel 2003 VBA Language Reference]
Returns or sets the color of the interior pattern as an index into the current color palette, or as one of the following XlColorIndex constants: xlColorIndexAutomatic or xlColorIndexNone. Read/write Long.
Set this property to xlColorIndexAutomatic to specify the automatic pattern for cells or the automatic fill style for drawing objects. Set this property to xlColorIndexNone to specify that you don't want a pattern (this is the same as setting the Pattern property of the Interior object to xlPatternNone).
The following illustration shows the color-index values in the default color palette.
This example sets the color of the interior pattern for rectangle one on Sheet1.
With Worksheets("Sheet1").Rectangles(1).Interior .Pattern = xlChecker .PatternColorIndex = 5 End With