First off i'll reference the original how-to for this:
http://forums.altimas.org/zerothread?id=340563
First thing i did was get a flathead screwdriver and a semi thick hand towel to wrap it around, then i started on the top right corner (where its thinnest) just as described in the original thread.
http://img413.imageshack.us/im...4.jpgh ... im...3.jpg
Be gentle with initial "digs" into the gap between the chrome and the grill as a the screwdriver head will cut through the towel and scratch the paint (very small scratches but still avoidable).
http://img370.imageshack.us/im...6.jpgh ... im...2.jpg
Once you get this top part loose I recommend using your fingers to pop out the brackets. You can wedge the screwdriver in the bottom-middle of the mustache (where its thickest) to loosen it up a bit if your fingers cant grab on initially. Your fingers will provide you better control and more power to remove the clips safely and you wont damage the paint.
http://img370.imageshack.us/im...6.jpg
Just repeat on the other side and your good-to-go!
http://img413.imageshack.us/im...5.jpg