icon directory question
 

can anyone out the tell me where the default icons for programs are kept? im wanting to change then so they show up on simple launcher like i want. i found a couple of files in /usr/share/pixmaps/ gpe contacts and canola were in there and i was able to change them. shows up in simple launcher like the should. and also in applicatin menu. are the rest hidded or is there a directory i can find them in?