It is a real pain in the ass to do by yourself. You will see a little tab on the top and bottom of each mounting point. You need to basically push in both tabs, at the same time pull the grill out. You will need to do this for each of the 6 (i think 6) mounting points. So somebody will have to be pulling the whole time or the clips will snap back into place. You can use a long skinny screwdriver or something similar to reach the tabs.
The nice thing is that if you don't break the clips you can re-install the grill in about 20 seconds.