Excel 2007 - Macro to insert entire row based on criteria

I am looking for a Macro that will insert an entire row across a number of collumns when there is a change in one column's data.
Example:
A B C
1 X Y
2 X Z
3 Y A

Change into
A B C
1 X Y
2 X Z
3 Insert Blank Row
4 Y A

Hopefully this is clear.

Dear slepchen:

I do understand but a macro is very specific and I would need to know what this criteria is