How do I make Sheet Code available in all sheets

I found sheet code on the forum that highlights the both the entire row and column when a cell is selected.

This is great, but is there a way I can make this an add-in so it is easily available in all workbooks and sheets?

Thanks!

Code:

Sub Worksheet_SelectionChange(ByVal Target As Excel.Range)
   Cells.Interior.ColorIndex = -4142
   Target.EntireRow.Interior.ColorIndex = 8
   Target.EntireColumn.Interior.ColorIndex = 8
End Sub