Write Application ICON at an EXE file

Hello everyone.

I deadly need an API call or pure source which will help me CHANGE an icon of an EXE file name. You know the API ExtractIconEx which gives the icon of an exe or dll library, i need to do exacly the opposite! I need to WRITE at an exe name a new icon for it. (Like Microangelo Does if you know it)

Thanks a lot, I am waiting for replies!
:)