in winscp, host name=ip address of iphone, port=22, username=root, password=alpine(1.1.1 Firmware) or dottie(older firmware), now click login
a window will pop up warning about host keys, click yes
now the browser will pop up, the left side=your computer, the right side=iphone.
on the iphone side, navigate to /Applications
in each folder for each application there will be a picture called icon.png, that is application icon, and the one you will replace with your own icon.
there are a few exceptions to the icon.png rule.
in the 1.1.1 firmware the ipod icon=icon-MediaPlayer.png