Removing Front Plastic Panels

I recently bought a new set of component speakers for my 2002 Xterra. When I went to put them in, I had some problems trying to remove the front plastic panels. Does anybody know of any internet sites that describes and shows (in pictures) how to remove these panels so that the speakers may be installed? Also, what is the best way to replace the old tweeters?

X4x4

http://www.automotiveforums.com/vbulletin/showthread.php?t=157161
Then go here:
http://www.automotiveforums.com/vbulletin/forumdisplay.php?f=816
or here:
http://www.automotiveforums.com/vbulletin/forumdisplay.php?f=818
... for solid reference material and a better place to inquire for more info.

Thank you, drive through,
Brent